Abstract:
A touch panel and a touch electrode structure thereof are provided. The touch electrode structure defines position units and includes electrodes electrically insulated from each other. Each of the electrodes covers more than one of the position units and comprises a plurality of sub-electrodes electrically insulated from each other. Each of the sub-electrodes includes sub-electrode units. Each of the position units is corresponding to at least one of the sub-electrode units of at least one of the sub-electrode, and combinations of the sub-electrode units of the different sub-electrodes in the respective position units are different. In the touch electrode structure, each electrode can be electrically independent without needing to dispose a jumper and an insulating layer, thus simplifying process steps and improving a yield rate at the same time.

Description:
[0001]    This application claims priority to Chinese Application Serial Number 201310516175.3, filed Oct. 28, 2013, which is herein incorporated by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of Invention 
         [0003]    The present invention relates to a field of a touching technology. More particularly, the present invention relates to a touch panel and a touch electrode structure thereof. 
         [0004]    2. Description of Related Art 
         [0005]    In the current market of consumer electronic products, a touch function combined into a display has become a trend of the mainstream for the development of portable electronic products. A touch panel has been applied to many kinds of electronic products such as smart phones, mobile telephones, tablet PCs and notebooks. Since a user can operate and issue a command through objects shown on a display, a touch panel provides a human interface between the user and the electronic product. 
         [0006]    In general, a touch panel includes a touching area and a peripheral area surrounding the touching area. The touching area is configured to generate a sensing signal, and several peripheral wires are disposed in the peripheral area for transmitting the sensing signal to a signal processing unit for computation, thereby determining a coordinate of a touch position. 
         [0007]    In a normal design of an electrode structure, please refer to  FIG. 1 , which illustrates a schematic diagram of a touch electrode structure of a conventional touch panel  100  in the prior art. As shown in  FIG. 1 , a touch electrode pattern  104  is formed on a touching area  102  of the touch panel  100 . The touch electrode pattern  104  includes horizontal electrodes  104   a  and vertical electrodes  104   b.  Each of the horizontal electrodes  104   a  and each of the vertical electrodes  104   b  are both constituted by connecting an electrode unit  104   c.  In this design, because the horizontal electrode  104   a  and the vertical electrode  104   b  intersect, a jumper  106  and an insulating layer  108  are used on the electrode pattern to isolate the horizontal electrodes  104   a  from the vertical electrodes  104   b.    
         [0008]    However, more than 5 lithography processes are generally needed if jumpers and insulating layers have to be disposed on the touch panel, and thus the fabrication of the conventional touch panel is complicated. Moreover, if one of the jumpers has an error, such as the jumper being broken or an electrostatic discharge, then the whole electrode will lose its functions. Therefore, the current industry still needs to improve the conventional touch electrode pattern used on the touch panel to reduce a production process and improve a yield rate. 
       SUMMARY OF THE INVENTION 
       [0009]    To solve the above problems, the present invention provides a novel touch electrode structure, in which each electrode can be electrically independent from each other without needing to dispose jumpers and insulating layers, thus simultaneously having advantages of simplified processes and an improved yield rate. 
         [0010]    According to an embodiment of the invention, a touch electrode structure is provided. Position units are defined in the touch electrode structure. The touch electrode structure includes electrodes electrically insulated from each other. Each of the electrodes covers more than one of the position units and includes sub-electrodes electrically insulated from each other. Each of the sub-electrodes includes sub-electrode units electrically connected to each other. Each of the position units is corresponding to at least one of the sub-electrode units of at least one of the sub-electrodes. In addition, combinations of the sub-electrode units from the different sub-electrodes in the respective position units are different. 
         [0011]    According to another embodiment of the invention, a touch panel is provided. The touch panel includes a base board on which position units are defined. Electrodes are disposed on the base board and are electrically insulated from each other. Each of the electrodes covers more than one of the position units and includes sub-electrodes. Each of the sub-electrodes includes sub-electrode units electrically connected to each other. Each of the position units is corresponding to at least one of the sub-electrode units of at least one of the sub-electrodes. In addition, combinations of the sub-electrode units from the different sub-electrodes in the respective position units are different. 
         [0012]    In the touch panel and the touch electrode structure provided in the invention, different touch position units are formed by different combinations of the sub-electrode units of different sub-electrodes. Therefore, no jumper or insulating layer is needed in the structure. The structure is simple and can achieve advantages of simplifying processes and improving a yield rate. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    The invention can be more fully understood by reading the following detailed description of the embodiment, with reference made to the accompanying drawings as follows: 
           [0014]      FIG. 1  is a top view illustrating a touch panel in the prior art; 
           [0015]      FIG. 2  is top view illustrating a touch panel according to an embodiment of the invention; 
           [0016]      FIG. 3  is a top view illustrating a touch panel according to another embodiment of the invention; 
           [0017]      FIG. 4  is a top view illustrating a touch panel according to yet another embodiment of the invention; and 
           [0018]      FIG. 5  is a top view illustrating a touch panel having electrode regions according to an embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0019]    Specific embodiments of the present invention are further described in detail below with reference to the accompanying drawings. 
         [0020]    At first, referring to  FIG. 2 , which is a top view illustrating a touch panel according to an embodiment of the invention. As shown in  FIG. 2 , a touch panel  200  of the invention includes a base board  201  used for carrying and protecting components disposed thereon. In addition, the base board  201  may be a cover glass, in which electrodes are disposed on one side of the base board  201 , and the other side can be used as a touching surface for a user. The base board  201  may be made of a hard material or a flexible transparent insulating material, such as glass, polyimide (PI), polypropylene (PP), polystyrene (PS), acrylonitrile-butadiene-styrene (ABS), polyethylene terephthalate (PET), polyvinyl chloride (PVC), polycarbonate (PC), polyethylene (PE), polymethyl methacrylate (PMMA), or polytetrafluoroethene (PTFE), etc. Position units  205  are defined on the base board  201 . Each position unit  205  represents the smallest sensing unit allowed on the touch panel. All of the position units  205  may be arranged irk an array to collectively compose a touching area of the touch panel 
         [0021]    Referring to  FIG. 2  again, electrodes  203 , which are electrically insulated from each other, are disposed on the base board  201 , and extend along a first direction D 1 . The electrodes  203  are arranged in parallel to each other, and cover position units  205  defined on the base board. A transparent conductive material such as indium tin oxide (ITO), indium zinc oxide (IZO), carbon nanotube (CNT) or nano silver may be used to form the electrodes  203  on the base board  201  by printing, lithography, laser etching, or the like. A feature of the invention is that each of the electrodes  203  is formed by plural sub-electrodes, and the sub-electrodes are electrically insulated from each other, such as four sub-electrode  203   a - 203   d  shown in the figure. Each of the sub-electrode  203   a - 203   d  is constructed by electrically connecting sub-electrode units  207  along the first direction D 1 , in which the connection may be achieved via transparent or opaque wires (now shown). The wires can be made of the same transparent conductive material used in the electrode unit  207 , or metal such as copper, molybdenum, aluminum and the like. To be more specific, in the invention, in order to achieve a function of determining a touching position, as shown in  FIG. 2 , each position unit  205  includes or corresponds to at least one sub-electrode unit  207 . More importantly, the sub-electrode units  207  that each of the position unit  205  includes or is corresponding to are determined according to combinations of the sub-electrode units  207  of different sub-electrodes  203   a - 203   d.  The detail will be described below. 
         [0022]    Three different position units  205   a,    205   b  and  205   c  shown in  FIG. 2  are used as examples. The position unit  205   a  includes three sub-electrode units  207 . The three sub-electrode units  207  respectively belong to the sub-electrodes  203   a - 203   c,  and extend along a second direction D 2  perpendicular to the first direction D 1 . The position unit  205   b  only includes one sub-electrode unit of the sub-electrode  203   c,  and the position unit  205   c  includes sub-electrode units of the sub-electrodes  203   a  and  203   d.  A sum of areas of the sub-electrode units  207  in a position unit  205  is approximately equal to the area of the position unit. However, the area and the number of the sub-electrode units  207  included in each position unit  205  may not be equal to each other completely. In the invention, because combinations of the sub-electrode units in the sub-electrodes which the respective position units  205  correspond to are different, this design can give an unique identification to each position unit  205 . That is, each position unit  205  uniquely corresponds to a combination of the sub-electrode units from different sub-electrodes. For example, in an implementation, when a user touches or approximates the position unit  205   a  on the base board with his/her finger or another touching object, the electrical signal (e.g. a voltage or a current caused by a mutual capacitance) at the position unit  205   a  will change. Because the position unit  205   a  includes the sub-electrode units of the sub-electrodes  203   a - 203   c,  the change of the electrical signal will result in changes of sensing signals of scanning outputs of the sub-electrodes  203   a - 203   c.  On the other hand, the sensing signal outputted from the sub-electrode  203   d  will not be affected, or the change thereof is very small compared to the changes of the sensing signals from the sub-electrodes  203   a - 203   c.  Therefore, a system may determine a touching position according to which sub-electrode outputs a sensing signal being changed or according to a magnitude of the change. For example, when the system synchronously inputs a driving signal to the sub-electrodes  203   a - 203   d  and then scans the sub-electrodes  203   a - 203   d  individually, if it detects that the sensing signals outputted from the sub-electrodes  203   a - 203   c  change, meaning that the touching position occurs at the position unit  205   a  exactly and simultaneously having the sub-electrode units of the sub-electrodes  203   a - 203   c.  Hence, based on the determination mechanism of the invention, as long as the permutations and the combinations of the sub-electrode units included in and corresponding to the respective position units  205  are different, the system is able to determine which position unit  205  that a touch is occurring on according to the change of the sensing signal from each sub-electrode. A single electrode  203  formed by four different sub-electrodes  203   a - 203   d  shown in  FIG. 2  is used as an example. Under the premise that each position unit  205  can include at most four sub-electrode units  207 , the combination of the sub-electrode units  207  has C 1   4 +C 2   4 +C 3   4 +C 4   4 =4+6+4+1=15 possibilities (including a situation of single sub-electrode unit). According to this design, 15 position units  205  can be successively disposed on each electrode  203  along the first direction D 1 . If an electrode row needs to include more position units  205  due to some invention requirements, the number of the combinations can be increased by increasing the number of the sub-electrodes of the electrodes  203 . Furthermore, the design of the invention uses the combinations of the sub-electrode units of plural sub-electrodes to correspond to each of the position units. Compared to a conventional skill in which a wire is disposed on each position unit to connect with a controller, the design of the invention can decrease the number of the wires connected to the controller so as to reduce the area of the peripheral area occupied by the wires, thus benefiting a narrow border design of a touch panel. 
         [0023]    Referring to  FIG. 3 ,  FIG. 3  is a top view illustrating a touch panel according to another embodiment of the invention. A difference between the pattern of the touch electrode in  FIG. 2  and that in  FIG. 3  is that the electrode  203  in  FIG. 3  is constructed by five different sub-electrodes  203   a - 203   e  instead of four sub-electrodes, and each position unit  205  includes at most two sub-electrode units  207 . In this configuration, the combination of the sub-electrode units  207  has C 1   5 +C 2   5 =5+10=15 possibilities, and the number of the combinations is equal to the number thereof in  FIG. 2 . It is understood that the combinations of the sub-electrode units in five sub-electrodes  203   a - 203   e  of the present embodiment may also use the method shown in  FIG. 2 , such that the number of the combinations of the sub-electrode units in the sub-electrodes  203   a - 203   e  will increase with the additional sub-electrode. Therefore, the number of the position units  205  included in the single electrode  203  will increase accordingly, and is suitable for use in touch panel designs with different sizes. 
         [0024]    Referring to  FIG. 4 ,  FIG. 4  is a top view illustrating a touch panel according to yet another embodiment of the invention. A difference between the patterns of the touch electrode in  FIG. 4  and that in  FIG. 3  is that the electrode  203  in  FIG. 4  is constructed by six different sub-electrodes  203   a - 203   f  instead of five ones, and the number of the sub-electrode units  207  corresponding to each position unit  205  is the same. A condition that each position unit  205  corresponds to two sub-electrode units is used as an example herein. In this configuration, there are C 2   6 =15 combinations of the sub-electrode units, and the number of the combinations is equal to the numbers thereof in  FIGS. 2 and 3 . 
         [0025]    Three different position units  205   a,    205   b  and  205   c  shown in  FIG. 4  are as examples, in which each of the position units  205   a,    205   b  and  205   c  includes two different sub-electrode units  207 . The position unit  205   a  includes the sub-electrode units  207  respectively belonging to the sub-electrodes  203   d  and  203   f.  The position unit  205   b  includes the sub-electrode units  207  respectively belonging to the sub-electrodes  203   e  and  203   f.  The position unit  205   c  includes the sub-electrode units  207  respectively belonging to the sub-electrodes  203   a  and  203   b.  In the invention, because the combinations of the sub-electrode units in the sub-electrode which the respective position units  205  correspond to are different, the design may give each position unit  205  an unique identification, that is, each position unit  205  is uniquely corresponding to a combination of the sub-electrode units of different sub-electrodes so as to achieve the function of determining touch positions. For example, while a touch sensing is performed, each electrode  203  is driven and scanned. Vertical coordinates of different touch points can be determined according to changes of sensing signals sent from the electrodes  203  located at different row locations. Horizontal coordinates (corresponding to horizontal coordinates of the respective position units  205 ) of the touch points can be determined according to the combination of the sub-electrode units of the different sub-electrodes included in the position units  205 . For example, the horizontal coordinates of different position units  205   a,    205   b  and  205  can be determined according to the following method. Every two sub-electrodes respectively are collaborated for driving and scanning. For example, the sub-electrode  203   a  is driven, and the sub-electrodes  203   b,    203   c,    203   d,    203   e  and  203   f  are respectively scanned (sensed); alternatively, the sub-electrode  203   b  is driven, and the sub-electrodes  203   a,    203   c,    203   d,    203   e,  and  203   f  are respectively scanned (sensed), and so on. If a touch point is at the position unit  205   a,  the sensing signal obtained by driving the sub-electrode  203   d  and scanning the sub-electrode  203   f  will change because the sub-electrode units  207  included in the position unit  205   a  are belonging to the electrodes  203   d  and  203   f;  and the sensing signals obtained from other combinations for driving and scanning, such as driving the sub-electrode  203   c  and scanning the sub-electrodes  203   a,    203   b,    203   d,    203   e  and  203   f,  will not change. If the touch position is at the position unit  205   b,  the sensing signal obtained by driving the sub-electrode  203   e  and scanning the sub-electrode  203   f  will change because the sub-electrode units  207  included in the position unit  205   b  are belonging to the electrodes  203   e  and  203   f;  and the sensing signals obtained from other combinations of driving and scanning, such as driving the sub-electrode  203   e  and scanning the sub-electrodes  203   a,    203   b,    203   c,    203   d  and  203   f,  will not change. If the touch position is at the position unit  205   c,  the sensing signal obtained by driving the sub-electrode  203   a  and scanning the sub-electrode  203   b  will change because the sub-electrode units  207  included in the position unit  205   b  are belonging to the electrodes  203   a  and  203   b;  and the sensing signals obtained from other combinations of driving and scanning, such as driving the sub-electrode  203   a  and scanning the sub-electrodes  203   c,    203   d,    203   e,  and  203   f,  will not change. Accordingly, the horizontal coordinates of different touch positions can be distinguished. The embodiment merely describes one of scanning and sensing methods, and the invention is not limited thereto. In the present embodiment, the numbers of the sub-electrode units  207  included in and corresponding to different position units  205  are the same and are fewer than that in  FIG. 2 , which may reduce signal interference between different sub-electrodes so as to increase touch panel precision. 
         [0026]    It can be known from the embodiments of  FIG. 2  to  FIG. 4  that, the number of the position units  205  covered by and corresponding to a single row of electrodes  203  can be determined according to the number of the sub-electrodes constituting the electrode  203  and the number of the sub-electrode units  207  that one position unit  205  can include. Increasing the numbers of the sub-electrodes and the sub-electrode units included therein can increase the number of the position units. However, the area of the sub-electrode unit  207  has to be reduced when the number of the sub-electrode units  207  included by the single position unit  205  is increased, thus decreasing touching sensitivity. Therefore, in the invention, how many sub-electrodes used in each electrode and the number of the sub-electrode units  207  included in each position unit  205  can be decided according to the number of the position units required in practical configurations and the required touching sensitivity. 
         [0027]    The advantages of the touch electrode structure and the touch panel provided by the invention are that, in a circuit design, only one conducting layer is needed to complete the entire touch electrode structure by patterning, without needing to use a jumper to connect the electrode units of the same electrode in the prior art, because each electrode  230  and each sub-electrode do not intersect. This circuit design has a simple structure, requires fewer process steps, has better reliability, and does not have the problems such as broken jumpers and electrostatic discharges that often occur. 
         [0028]    On the other hand, referring to  FIG. 5 ,  FIG. 5  is a top view illustrating a touch panel having electrode regions according to an embodiment of the invention. In the implementation, in response to larger-size panel designs, electrode regions may be defined on the base board  201  for arranging the electrodes extending along different directions. For example, as shown in  FIG. 5 , the electrodes disposed in an electrode region  209   a  extend along the first direction D 1 , and the electrodes disposed in an electrode region  209   b  extend along the second direction D 2  perpendicular to the first direction D 1 . This design can significantly reduce the number of the position units required to be covered by each electrode, so as to avoid using too many sub-electrodes and increasing the complexity of the circuit design. It is noted that the directions with which the electrodes may extend are not limited to the horizontal direction and the vertical direction shown in the figure, but the electrodes may be disposed inclined with respect to the periphery areas. 
         [0029]    Although the present invention has been described in considerable detail with reference to certain embodiments thereof, other embodiments are possible. Therefore, the spirit and scope of the appended claims should not be limited to the description of the embodiments contained herein. It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims.