Patent Publication Number: US-2015060120-A1

Title: Touch panel

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of Korean Patent Application No. 10-2013-0103192 filed on Aug. 29, 2013, and Korean Patent Application No. 10-2014-0111024 filed on Aug. 25, 2014 with the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference. 
     BACKGROUND 
     The present disclosure relates to a touch panel. 
     In general, a touchscreen apparatus such as a touchscreen, a touch pad, or the like, a device user interface attached to a display apparatus to provide an intuitive user interface, has recently been widely used in various electronic apparatuses such as cellular phones, personal digital assistants (PDAs), navigation apparatuses, and the like. Particularly, as demand for smartphones has recently increased, the use of touchscreens capable of providing various user interface methods in a limited form factor has correspondingly increased. 
     Touchscreens used in portable apparatuses may mainly be divided into resistive type touchscreens and capacitive type touchscreens, according to a method of sensing a touch implemented therein. Here, capacitive type touchscreens have advantages in that they have a relatively long lifespan and various types of touches and gestures may be easily used therewith, such that the use thereof has increased. Particularly, capacitive type touchscreens may more easily allow for a multi-touch interface to be realized, as compared with resistive type touchscreens, such that they are widely used in apparatuses such as smartphones, and the like. 
     Capacitive type touchscreens include a plurality of electrodes having a predetermined pattern and forming a plurality of nodes in which changes in capacitance are generated by touches. In the plurality of nodes distributed on a two-dimensional plane, changes in self-capacitance or in mutual-capacitance may be generated by touches. Coordinates of a touch may be calculated by applying a weighted average method, or the like, to changes in capacitance generated in the plurality of nodes. 
     In a touch panel according to the related art, a sensing electrode recognizing a touch is generally formed of indium tin oxide (ITO). However, ITO is relatively expensive and is not particularly competitive in terms of price, since indium used as a raw material thereof is a rare earth metal. In addition, indium reserves are expected to be depleted within the next decade, such that indium may not be easily supplied in the future. Research into technology for forming electrodes using opaque conductive lines for the reasons mentioned above has been conducted. Here, such electrodes formed of the conductive lines may have better conductivity than that of the ITO or conductive polymer and the supply thereof may be smoothly performed. However, in order to use conductive lines as electrodes for a touchscreen, transparency and invisibility should be increased and terminal resistance should be suppressed. 
     Patent Document 1 of the following related art document discloses increasing an area of a sensor electrode and decreasing a distance at an edge portion in order to reinforce output coordinates of the edge portion in the capacitive type touchscreen, but this configures the electrode using the ITO, and does not disclose implementing the electrode using the conductive lines, in which the conductive lines of an effective region and an a bezel region have different opening ratios. 
     RELATED ART DOCUMENT 
     
         
         [Patent Document] Korean Patent Laid-Open Publication No. 10-2013-0044432 
       
    
     SUMMARY 
     An exemplary embodiment in the present disclosure may provide a touch panel having improved transparency in the touch panel in an effective region, preventing the disconnection of conductive lines in a bezel region, and decreasing a resistance value by allowing the conductive lines formed in a mesh pattern in the effective region and the bezel region to have different opening ratios. 
     According to an exemplary embodiment in the present disclosure, a touch panel may include: a substrate; and electrode parts having a plurality of electrodes formed on the substrate, wherein the electrode parts include a plurality of conductive lines formed in a mesh pattern and have different opening ratios for a plurality of respective regions of the substrate. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other aspects, features and other advantages in the present disclosure will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a perspective view illustrating the exterior of an electronic apparatus including a touch panel according to an exemplary embodiment in the present disclosure; 
         FIG. 2  is a front view of the touch panel according to an exemplary embodiment in the present disclosure; 
         FIG. 3  is a front view illustrating the touch panel according to an exemplary embodiment of  FIG. 2  in greater detail. 
         FIG. 4  is a cross-sectional view of the touch panel according to an exemplary embodiment in the present disclosure; 
         FIG. 5  is a partially-enlarged view of conductive lines according to an exemplary embodiment in the present disclosure; and 
         FIGS. 6 through 8  are perspective views illustrating touch panels according to various exemplary embodiments in the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, embodiments in the present disclosure will be described in detail with reference to the accompanying drawings. 
     The disclosure may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. 
     In the drawings, the shapes and dimensions of elements may be exaggerated for clarity, and the same reference numerals will be used throughout to designate the same or like elements. 
       FIG. 1  is a perspective view illustrating the exterior of an electronic apparatus including a touch panel according to an exemplary embodiment in the present disclosure. 
     Referring to  FIG. 1 , an electronic apparatus  100  according to the present embodiment may include a display apparatus  110  for outputting an image, an input unit  120 , an audio unit  130  for audio output, and a touchscreen apparatus (not shown) integrated with the display apparatus  110 , wherein a touch panel may be included in the touchscreen apparatus. 
     The touchscreen apparatus may include a substrate and a touch panel having a plurality of electrodes provided on the substrate. Also, the touchscreen apparatus according to an exemplary embodiment in the present disclosure may include a controller integrated circuit (touch sensing apparatus) including a capacitance detection circuit detecting changes in capacitance generated in the plurality of electrodes, an analog-to-digital conversion circuit converting an output signal from the capacitance detection circuit into a digital value, an operation circuit determining a touch by using data converted as the digital value, and the like. 
       FIG. 2  is a front view of the touch panel according to an exemplary embodiment in the present disclosure. 
     Referring to  FIG. 2 , a touch panel  200  according to the present exemplary embodiment may include a substrate  210 , electrode parts  220  provided on the substrate  210 , pad parts  230  including a plurality of pads connected to the electrode parts  220 , respectively, and a bezel portion  240 . 
     Although not illustrated in  FIG. 2 , the pad parts  230  connected to the electrode parts  220 , respectively, may be electrically connected to a flexible printed circuit board attached to one end of the substrate  210  through wirings and bonding pads. A controller integrated circuit is mounted on the circuit board to detect a sensing signal generated in the electrode part  220  and determine a touch from the sensing signal. 
     Therefore, the substrate  210  may be formed of a material for a film such as polyethylene terephtalate (PET), polycarbonate (PC), polyethersulfone (PES), polyimide (PI), polymethylmethacrylate (PMMA), cyclo-olefin polymers (COP), or the like, soda glass, or tempered glass. 
     The electrode parts  220  may include the first electrodes  223  extending in an X-axis (first axial) direction and the second electrodes  226  extending in a Y-axis (second axial) direction. The first electrodes  223  and the second electrodes  226  may intersect with each other on both surfaces of the substrate  210 , or on different substrates  210 . In the case in which the first electrodes  223  and the second electrodes  226  are both formed on one surface of the substrate  210 , predetermined insulating layers may be partially formed in intersections between the first electrodes  223  and the second electrodes  226 . 
     The apparatus electrically connected to the electrode parts  220  to sense a touch may detect changes in capacitance generated in the electrode parts  220  according to a touch applied thereto and sense the touch therefrom. The first electrode  223  may be connected to channels D1 to D8 in the controller integrated circuit to thereby have a predetermined driving signal applied thereto, and the second electrode  226  may be connected to channels S1 to S8 to be used for the touch sensing apparatus to detect sensing signals. In this case, the controller integrated circuit may detect the changes in capacitance generated between the first electrode  223  and the second electrode  226  to thereby obtain the sensing signals and may be operated in a scheme in which driving signals are sequentially applied to each of the first electrodes  223  and simultaneously detects the changes in capacitance in the second electrodes  226 . 
     When the driving signals are applied to the first electrodes  223  through the channels D1 to D8, mutual capacitance may be generated between the first electrodes  223  to which the driving signals are applied and the second electrodes  226 . In the case in which a touch object contacts the touch panel, the change in capacitance may be generated in the mutual capacitance, wherein the change in capacitance may be in proportion to an area of the touch object. 
       FIG. 3  is a view illustrating the touch panel according to an exemplary embodiment of  FIG. 2  in greater detail. 
     Referring to  FIG. 3 , the electrode parts  220  may be formed of conductive lines, wherein the conductive lines forming the electrode parts  220  may have a net or mesh pattern. In the case in which the conductive lines are formed in the net or the mesh pattern, a phenomenon in which a patterning mark is visible in a region in which an indium-tin oxide electrode conventionally exists may be decreased and transparency of the touch panel may be improved. 
     Although  FIG. 3  shows a case in which the conductive lines forming the electrode parts  220  are formed in a rhomboid or rectangular pattern, the pattern of the conductive lines is not limited thereto, and the pattern of the conductive lines according to the present disclosure may include a range apparently or easily deducted by those skilled in the art such as a hexagon, an octagon, a diamond pattern, a random pattern, and the like. 
     The conductive lines forming the electrode parts  220  may be manufactured by using one of silver (Ag), aluminium (Al), chromium (Cr), nickel (Ni), molybdenum (Mo), and copper (Cu), or alloys thereof. In the case in which the electrode parts  220  are manufactured of a metal, a resistance value of the electrode may be decreased, such that conductivity and detecting sensitivity thereof may be improved. 
     The pad part  230 , the wirings for electrically connecting the pad part  230  and the circuit board to each other, the bonding pad, and the like may be typically formed of an opaque metal material, wherein in order to visually shield the pad part  230 , the wiring, and the bonding pad, the bezel portion  240  may be formed in a predetermined region of the substrate  210 . 
     The bezel portion  240  may be formed in a region of the substrate  210  except for a region (a view region) to which an image is output or a region (an active region) to which the touch is applied in a display apparatus having the touch of the user applied thereto and formed integrally with the touch panel, wherein the bezel portion  240  may be generally positioned on edges of the substrate  210 . Hereinafter, the region having the bezel portion  240  formed thereon is referred to as a bezel region and other regions are referred to as effective regions for convenience of explanation. 
       FIG. 4  is a cross-sectional view of the touch panel according to an exemplary embodiment in the present disclosure. 
     Referring to  FIG. 4 , the bezel portion  240  is formed on the substrate  210  to be wider than the region having the pad parts  230  formed thereon in order to more reliably shield the opaque pad parts  230 . Although the present exemplary embodiment illustrates a case in which the bezel portion  240  is stacked on the substrate  210 , the bezel portion  240  may be embedded in the substrate  210 . The conductive lines of the electrode parts  220  may be extended to the bezel portion  240  side and may be connected to the pad part  230 . 
       FIG. 5  is a partially-enlarged view of conductive lines according to an exemplary embodiment in the present disclosure. An opening ratio of the electrode part  220  may be defined by a pitch T and a line width d of the conductive line. As the pitch T is large and the line width d is narrow, the opening ratio of the electrode part  220  may be increased. Generally, a relationship between the opening ratio to of the electrode part  220 , and the pitch T and the line width d may be represented by the following Equation 1. 
     
       
         
           
             
               
                 
                   to 
                   = 
                   
                     
                       ( 
                       
                         
                           T 
                           - 
                           d 
                         
                         T 
                       
                       ) 
                     
                     2 
                   
                 
               
               
                 
                   [ 
                   
                     Equation 
                      
                     
                         
                     
                      
                     1 
                   
                   ] 
                 
               
             
           
         
       
     
       FIGS. 6 through 8  are perspective views illustrating touch panels according to various exemplary embodiments in the present disclosure. In  FIGS. 6 through 8 , planes illustrated over the touch panel  200  are not actually present, but illustrate regions formed by dividing the substrate  210  to illustrate the opening ratio of the electrode part  220 . 
     Referring to  FIG. 6 , the electrode parts formed in the effective region A and the bezel region B of the substrate  210  may have different opening ratios. As described above, the effective regions A of the touch panel correspond to those to which the display screen is output and the touch is input. In order to increase transparency of the touch panel and invisibility of the conductive lines, the opening ratio of the electrode part  220  formed in the effective region A may be set to be higher than that of the electrode part  220  formed in the bezel region B. In addition, the bezel region B may have the opening ratio set to be lower than that of the effective regions A to have decreased resistance and prevent the conductive lines from being disconnected due to a step caused by a bezel portion  240  that may be formed in the bezel region B. 
     In this case, the opening ratio of the electrode part  220  formed in the bezel region B may be 20% to 80% of the opening ratio of the electrode part  220  formed in the effective region A. 
     The following Table 1 indicates disconnection rates of conductive lines in the bezel region B and line widths of conductive lines in the effective region A, in response to a ratio (B/A) of the opening ratio of the electrode part formed in the bezel region B to the opening ratio of the electrode part formed in the effective region A. In the following Table 1, the line width of the conductive line in the effective region A corresponds to a line width of a conductive line actually manufactured according to the ratio (B/A) of the opening ratios in the case that a target line width of the conductive line is 3 μm. 
     Referring to the following Table, when the ratio (B/A) of the opening ratios is less than 20%, it could be confirmed that the disconnection ratio of the conductive line in the bezel region B is low, but a difference between the target line width and the actually manufactured line width is significantly generated. In the case that a significant difference in opening ratio is present between the effective region A and the bezel region B, in the case of electrodes provided in the bezel region B, a large amount of portions to be etched may be present while in the case of electrodes provided in the effective region A, a small amount of portions to be etched may be present. As areas in which etching is performed are different, the actually manufactured line width may be wider than the target line width. 
     In addition, when the ratio (B/A) of the opening ratios is greater than 80%, the target line width and the actually manufactured line width may be equal to each other, but the disconnection ratio of the conductive line in the bezel region B may be sharply increased. 
     According to an exemplary embodiment, the opening ratio of the electrode part  220  formed in the bezel region B may be set to 20% to 80% of the opening ratio of the electrode part  220  formed in the effective region A, such that the difference between the target line width and the actually manufactured line width may be decreased, and the disconnection of the conductive line in the bezel region B may be prevented. 
     
       
         
           
               
               
            
               
                   
                   
               
               
                   
                 Ratio (B/A) of Opening Ratios 
               
            
           
           
               
               
               
               
               
               
               
               
               
               
               
            
               
                   
                 10% 
                 20% 
                 30% 
                 40% 
                 50% 
                 60% 
                 70% 
                 80% 
                 90% 
                 100% 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
               
               
            
               
                 Line Width 
                 7~10 μm 
                 5~6 μm 
                 4 μm 
                 3.5 μm 
                 3 μm 
                 3 μm 
                 3 μm 
                 3 μm 
                 3 μm 
                 3 μm 
               
               
                 of Conductive 
               
               
                 Line in Effective 
               
               
                 Region A 
               
               
                 Disconnection Rate 
                 0% 
                 0% 
                 1% 
                 1% 
                 3% 
                 4% 
                 5% 
                 7% 
                 12% 
                 19% 
               
               
                 of Conductive 
               
               
                 Line in Bezel 
               
               
                 Region B 
               
               
                   
               
            
           
         
       
     
     Specifically, in the case in which the pitch of the conductive lines is identical in the cases of the effective region A and the bezel region B, the line width of the conductive lines in the bezel region B may be 100% to 400% of the line width of the conductive lines in the effective region A. Since the line width of the conductive lines in the effective region A may be set to 0.5 μm to 6 μm, the line width of the conductive lines in the bezel region B may be set to 0.5 μm to 24 μm. 
     In a case in which the line width of the conductive lines is identical in the cases of the effective region A and the bezel region B, the pitch of the conductive lines in the bezel region B may be 50% to 100% of the pitch of the conductive lines in the effective region A. Since the pitch of the conductive lines in the effective region A may be set to 20 μm to 500 μm, the pitch of the conductive lines in the bezel region B may be set to 10 μm to 500 μm. 
     The opening ratios may be differentially set by simultaneously setting the line width and the pitch to be different. 
     Meanwhile, areas of the effective region A and the bezel region B may be changed by a setting. As an example, the bezel region B may have the area of 1% to 5% of that of the effective region A. 
       FIG. 7  is a view illustrating the touch panel according to an exemplary embodiment in the present disclosure. In describing the touch panel according to an exemplary embodiment in the present disclosure of  FIG. 7 , a description for the same portions thereof as those of the touch panel of  FIG. 6  will be omitted and portions thereof different from those of the touch panel of  FIG. 6  will be mainly described. 
     Referring to  FIG. 7 , the bezel region B of  FIG. 7  may include a plurality of bezel regions B1 and B2. Specifically, the bezel region B may include a first bezel region B1 and a second bezel region B2. Although not specifically illustrated in  FIG. 7 , the substrate  210  may be bonded and electrically connected to a flexible printed circuit board  300 . Specifically, the wiring patterns and the bonding pads connected to the pad parts  230  may be formed on the bezel portion  240  of the substrate  210 . Here, the bonding pads may be electrically connected to the flexible printed circuit board  300  through an anisotropic conductive film (ACF). 
     The first bezel region B1 may be a region schematically illustrating a portion relatively adjacent to the flexible printed circuit board  10  among the bezel region B and the second bezel region B2 may be a region schematically illustrating a portion relatively distant from the flexible printed circuit board  10  among the bezel region B. The resistance value of the electrode part  220  may be increased as a distance between the electrode part  220  and the flexible printed circuit board  10  is increased. In the case in which the electrode parts  220  of the first bezel region B1 and the second bezel region B2 have the same opening ratio, the electrode part  220  of the second bezel region B2 may have the resistance value higher than that of the electrode part  220  of the first bezel region B1. 
     According to an exemplary embodiment in the present disclosure, the resistance value may be decreased by setting an opening ratio of the electrode part  220  formed in the second bezel region B2 to be different from an opening ratio of the electrode part  220  formed in the first bezel region B1. Specifically, the electrode part  220  formed in the second bezel region B2 may have the opening ratio lower than that of the electrode part  220  formed in the first bezel region B1. The line width of the conductive lines of the electrode part  220  formed in the second bezel region B2 is set to be thicker than that of the electrode part  220  formed in the first bezel region B1, the pitch of the conductive lines of the electrode part  220  formed in the second bezel region B2 is set to be smaller than that of the electrode part  220  formed in the first bezel region B1, or both of the line width and the pitch are changed, such that the resistance value of the electrode part  220  formed in the second bezel region B2 may be decreased. 
     Although  FIG. 7  illustrates a case in which the bezel region B is divided into the first bezel region B1, having a “ ” shape and the second bezel region B2, having an “|” shape, the bezel region B may be divided into various shapes in addition to the above-mentioned shapes. In addition, although  FIG. 7  illustrates a case in which the bezel region B is divided into two bezel regions B1 and B2, the bezel region may be divided into three or more regions in addition to the two regions. 
       FIG. 8  is a view illustrating the touch panel according to an exemplary embodiment in the present disclosure. In describing the touch panel according to an exemplary embodiment in the present disclosure of  FIG. 8 , a description for the same portions thereof as those of the touch panel of  FIG. 6  will be omitted and portions thereof different from those of the touch panel of  FIG. 6  will be mainly described. 
     Referring to  FIG. 8 , the effective region A of  FIG. 7  may include a plurality of effective regions A1 and A2. The plurality of effective regions A1 and A2 may have predetermined areas depending on a distance between the plurality of effective regions A1 and A2 and the central point of the substrate  210 . In this case, the plurality of respective effective regions A1 and A2 may have different opening ratios. In this case, a region having a distance close to the central point may have the opening ratio higher than that of a region having a distance distant from the central point. 
     Specifically, the effective region A may include a first effective region A1 and a second effective region A2. In this case, the electrode parts  220  formed in the first effective region A1 and the second effective region A2 may have different opening ratios. The electrode part  220  formed in the first effective region A1 may have the opening ratio higher than that of the electrode part  220  formed in the second effective region A2. In this case, the electrode part  220  formed in the second effective region A2 may have the opening ratio higher than that of the electrode part  220  formed in the bezel region B. 
     The opening ratio of the electrode part  220  formed in the first effective region A1 positioned at the central point of the substrate  210  is set to be higher than that of the electrode part  220  formed in the second effective region A2 distant from the central point, such that transparency of the touch panel and invisibility of the conductive lines in the central portion of the effective region A may be increased. 
     Although  FIG. 8  illustrates a case in which the effective region A is divided into the first effective region A1 and the second effective region A2 having a quadrangular shape, the effective region A may be divided into various shapes such as a circular shape, and the like in addition to the above-mentioned shape. In addition, although  FIG. 8  illustrates a case in which the effective region A is divided into two effective regions A1 and A2, the effective region may be divided into three or more regions in addition to the two regions. 
     Further, without dividing the effective region A and the bezel region B, the opening ratio may be set to be gradually increased from the bezel region side (an edge) of the substrate  210  to the central point of the substrate  210 . In this case, the opening ratio may be changed within a range of 10% to 99%, the line width may be changed within a range of 0.5 μm to 24 μm, and the pitch may be changed within a range of 10 μm to 500 μm. 
     As set forth above, according to exemplary embodiments in the present disclosure, transparency of the touch panel in the effective region may be improved, and the disconnection of the conductive lines in the bezel region may be prevented and the resistance value thereof may be decreased. 
     While exemplary embodiments have been shown and described above, it will be apparent to those skilled in the art that modifications and variations could be made without departing from the scope of the invention as defined by the appended claims.