Patent Publication Number: US-2013241851-A1

Title: Electrode unit with perimeter-lengthened touch-sensing pattern for touch-sensing element located at fringes of touch panel

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The disclosed embodiments of the present invention relate to a sensing pattern design, and more particularly, to an electrode unit with a perimeter-lengthened touch-sensing pattern on a touch-sensing element located at fringes of a touch panel. 
     2. Description of the Prior Art 
     Regarding a single-layered capacitive touch panel, a touch-sensing element on a touch panel is usually implemented using longitudinal electrodes and transverse electrodes with transparent conductive materials (e.g., indium tin oxide (ITO)). When a finger touches a longitudinal electrode and a transverse electrode, an inductive capacitance between the touched longitudinal electrode and transverse electrode alters responsively. The difference of the inductive capacitance before and after the touch can then be used to calculate where the contact is. 
     Please refer to  FIG. 1 , which is a schematic diagram illustrating an example of a sensing pattern of electrodes on a conventional touch panel TP. The touch panel TP includes a plurality of touch-sensing elements TU, where each of the touch-sensing elements TU has an electrode unit  100  thereon, and the electrode unit  100  includes at least a first transverse electrode  110  and a second longitudinal electrode  120 . As shown in  FIG. 1 , the touch-sensing elements TU are staggered as a rectangular pattern, and the first electrode  110  on the same row are series-connected as a sensing trace, and the second electrode  120  on the same column are series-connected as a sensing trace. In this way, the touch panel TP would have a plurality of transverse sensing traces T 1 -TN and a plurality of longitudinal sensing traces S 1 -SM. In addition, the electrode unit  100  also has a separation unit constituted by insulation material and disposed on an intersection of the corresponding first electrode  110  and second electrode  120 . Hence, the sensing traces T 1 -TN and sensing traces S 1 -SM would not be electrically connected. 
     However, since an area being able to induct the inductive capacitance between two adjacent electrodes (i.e., the first electrode  110  and the second electrode  120 ) on the touch-sensing element TU located on fringes of the touch panel TP is smaller than an area being able to induct the inductive capacitance between two adjacent electrodes (i.e., the first electrode  110  and the second electrode  120 ) on the touch-sensing element TU located in the middle of the touch panel TP, when the finger enters the touch panel TP from the fringe, the inductive capacitance sensed by the electrodes on the fringes is smaller than inductive capacitance sensed by the electrodes in an effective sensing area, which is prone to misjudgment. 
     Therefore, there is a need to enhance the inductive capacitance sensed by the electrodes of the touch-sensing element located on the fringes of the touch panel, in order to decrease the likelihood of faulty calculation of contact on the fringes of the touch panel. 
     SUMMARY OF THE INVENTION 
     In accordance with exemplary embodiments of the present invention, an electrode unit with a perimeter-lengthened touch-sensing pattern on a touch-sensing element located at fringes of a touch panel is proposed to solve the above-mentioned problem. 
     According to an aspect of the present invention, an exemplary electrode unit is disclosed. The electrode unit includes a first electrode, a second electrode, and a plurality of fifth conductive elements. The first electrode includes a first conductive element and a plurality of second conductive elements. The first conductive element has a plurality of first funnel-shaped notches. The plurality of second conductive elements extends from the first conductive element. The second electrode includes a third conductive element and a plurality of fourth conductive elements. The third conductive element has a plurality of second funnel-shaped notches. The plurality of fourth conductive elements extends from the third conductive element. The plurality of fifth conductive elements extends from the third conductive element. 
     Therefore, when deployed on the touch-sensing element located on the fringes of the touch panel, the present invention can decrease the likelihood of faulty calculation of contact on the fringes of the touch panel. 
     These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram illustrating an example of a sensing pattern of electrodes on a conventional touch panel. 
         FIG. 2A  is a top view illustrating an electrode unit on a touch-sensing element according to an embodiment of the present invention. 
         FIG. 2B  is a schematic diagram illustrating an embodiment of the first electrode in  FIG. 2A . 
         FIG. 2C  is a schematic diagram illustrating an embodiment of the second electrode in  FIG. 2A . 
         FIG. 3  is a schematic diagram illustrating a sensing pattern of electrode units shown in  FIG. 2A  on a touch panel according to an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Certain terms are used throughout the description and following claims to refer to particular components. As one skilled in the art will appreciate, manufacturers may refer to a component by different names. This document does not intend to distinguish between components that differ in name but not function. In the following description and in the claims, the terms “include” and “comprise” are used in an open-ended fashion, and thus should be interpreted to mean “include, but not limited to . . . ”. Also, the term “couple” is intended to mean either an indirect or direct electrical connection. Accordingly, if one device is electrically connected to another device, that connection may be through a direct electrical connection, or through an indirect electrical connection via other devices and connections. 
     When an object touches an electrode unit of a current touch-sensing element and an electrode unit on an adjacent touch-sensing element, a contact of the object can be determined by calculating the difference between an inductive capacitance C sensed by the electrode unit before and after the touch, and comparing the inductive capacitance C with an inductive capacitance C′ sensed by the electrode unit on the adjacent touch-sensing element. Therefore, a concept of the present invention is to increase the inductive capacitance C sensed by a touch-sensing element located on a fringe of a touch panel by increasing contact areas being able to induct the inductive capacitance C on an electrode unit of the touch-sensing element, such that accuracy of determining the contact of the object can be improved. More specifically, since an electrode itself has a certain thickness, the present invention may increase the contact areas being able to induct the inductive capacitance C by increasing a perimeter of a sensing pattern formed by the electrode unit. 
     Please refer to  FIG. 2A , which is a top view illustrating an electrode unit  200  on a touch-sensing element TU′ according to an embodiment of the present invention. In  FIG. 2A , the electrode unit  200  includes a first electrode  210  and a second electrode  220 . In addition, the electrode unit  200  also has a separation unit (not shown in  FIG. 2A ) constituted by insulation material and disposed at an intersection of the first electrode  210  and the second electrode  220  and located in between the first electrode  210  and the second electrode  220 , such that the first electrode  210  and the second electrode  220  are not electrically connected. Therefore, there may be an inductive capacitance inducted between the first electrode  210  and the second electrode  220 . 
     Please refer to  FIG. 2A  and  FIG. 2B  concurrently.  FIG. 2B  is a schematic diagram illustrating an embodiment of the first electrode  210  shown in  FIG. 2A . The first electrode  210  includes a first conductive element  212  and a plurality of second conductive element  214 _ 1 - 214 _ 4 . In this embodiment, the first conductive element  212  includes a wider part  212 _ 1  and a narrower part  21   2 _ 2 , where the wider part  212 _ 1  is located at a middle section of the first conductive element  212 , and a width W 1  of the wider part  212 _ 1  is greater than a width W 2  of the narrower part  212 _ 2  (i.e., W1&gt;W2). The first conductive element  212  has a plurality of first funnel-shaped notches H 1 _ 1  and H 1  _ 2  located on both sides of the wider part  212 _ 1 , respectively. In addition, each of the second conductive elements  214 _ 1 - 214 _ 4  is strip-shaped, and includes at least a first section L 1  and a second section L 2 . The first section L 1  extends outward from the first conductive element  212  in directions in parallel with a first direction D 1 , and the second section L 2  is not in parallel with the first section L 1 . In other words, a joint of the first section L 1  and its corresponding second section L 2  of each of the second conductive elements  214 _ 1 - 214 _ 4  forms a bent part. 
     Please note that, in this embodiment, the first section L 1  and its corresponding second section L 2  of each of the second conductive elements  214 _ 1 - 214 _ 4  are perpendicular to each other, and each of the second conductive elements  214 _ 1  - 214 _ 4  has only one bent part. However, it is for illustrative purpose only, and is not meant for a limitation of the present invention. For example, in another embodiment, at least one conductive element in the second conductive elements  214 _ 1 - 214 _ 4  may include a first section, a second section and a third section, where the first section is not in parallel with the second section, and the second section is not in parallel with the third section. At this moment, the conductive element that includes the first section, the second section and third section has two bent parts. That is, each of the conductive elements in the second conductive elements  214 _ 1 - 214 _ 4  has at least one bent part, and different conductive elements may have different numbers of bent parts. Besides, this embodiment uses  4  second conductive elements for illustrative purpose only, and it is not meant for a limitation of the present invention. Those skilled in the art should readily increase/decrease the number of second conductive elements according to actual design requirement. 
     In addition, the electrode unit  200  further includes a plurality of third conductive elements  216 _ 1  and  216 _ 2  straightly extending outward from two ends of the first conductive element  212  in directions in parallel with the first direction D 1 , respectively, so as to output a sensing signal SIG sensed by the first electrode  210 . The third conductive elements  216 _ 1  and  216 _ 2  are substantially strip-shaped, respectively. That is, the third conductive elements  216 _ 1  and  216 _ 2  may be considered as conductive wires, respectively, for outputting the sensing signal SIG. Please note that, in this embodiment, the first conductive element  212  and the second conductive elements  214 _ 1 - 214 _ 4  may be realized by indium tin oxide (ITO), and the third conductive elements  216 _ 1  and  216 _ 2  may also be realized by ITO, or realized by conductive metal (i.e., implemented in a metal layer of the touch-sensing element) based on actual requirement of signal output layouts. However, it is for illustrative purpose only, and is not meant for a limitation of the present invention. 
     Please refer to  FIG. 2A  and  FIG. 2C  concurrently.  FIG. 2C  is a schematic diagram illustrating an embodiment of the second electrode  220  shown in  FIG. 2A . The second electrode  220  includes a fourth conductive element  222 , a plurality of fifth conductive elements  224 _ 1 - 224 _ 4  and a plurality of sixth conductive elements  226 _ 1  - 226 _ 4 . The fourth conductive element  222  has a plurality of second funnel-shaped notches H 2 _ 1  and H 2 _ 2  located at both sides of the fourth conductive element  222 , respectively, and the fourth conductive element  222  together with the notches H 2 _ 1  and H 2 _ 2  may substantially form a rectangle. Each of the fifth conductive elements  224 _ 1 - 224 _ 4  is strip-shaped, and includes a first section L 1  and a second section L 2 . The first section L 1  extends outward from the fourth conductive element  222  in directions in parallel with a second direction D 2 , and the second section L 2  is not in parallel with the first section L 1 . In other words, a joint of the first section L 1  and its corresponding second section L 2  of each of fifth conductive elements  224 _ 1  - 224 _ 4  forms a bent part. In addition, each of sixth conductive elements  226 _ 1  - 226 _ 4  is strip-shaped, straightly extending outward from the fourth conductive element  222  in directions in parallel with a third direction D 3 , and the third direction D 3  is different from the second direction D 2  (in this embodiment, the second direction D 2  is perpendicular to the third direction D 3 , but it is for illustrative purpose only). However, when the touch-sensing element TU′ is located at one of the corners of the touch panel (e.g. an upper-left corner, an upper-right corner, a lower-left corner or a lower-right corner), the sixth conductive elements  226 _ 1 - 226 _ 4  would straightly extend outward in directions in parallel with the second direction D 2 . 
     Please note that, in this embodiment, the first section L 1  and its corresponding second section L 2  of each of fifth conductive elements  224 _ 1 - 224 _ 4  are perpendicular to each other, and each of the fifth conductive elements  224 _ 1  - 224 _ 4  has only one bent part. However, it is for illustrative purpose only, and is not meant for a limitation of the present invention. For example, in another embodiment, at least one conductive element in the fifth conductive elements  224 _ 1  - 224 _ 4  may include a first section, a second section and a third section, where the first section is not in parallel with the second section, and the second section is not in parallel with the third section. At this moment, the conductive element that includes the first section, the second section and third section has two bent parts. That is, each of the conductive elements in the fifth conductive elements  224 _ 1 - 224 _ 4  has at least one bent part, and different conductive elements may have different numbers of bent parts. Please note that, in this embodiment, the fourth conductive element  222 , the fifth conductive elements  224 _ 1 - 224 _ 4  and the sixth conductive element  226 _ 1 - 226 _ 4  may be realized by ITO. In addition, this embodiment uses 4 fifth conductive elements and 4 sixth conductive elements for illustrative purpose only, and it is not meant for a limitation of the present invention. Those skilled in the art should readily increase/decrease the number of fifth conductive elements and the number of sixth conductive elements according to actual design requirement. 
     Please refer to  FIG. 3 , which is a schematic diagram illustrating a sensing pattern of electrode units  200  on a touch panel TP′ according to an embodiment of the present invention. In this embodiment, the touch panel TP′ includes a plurality of touch-sensing elements TU shown in  FIG. 1  that are orderly arranged in the middle of the touch panel TP′, and further includes a plurality of touch-sensing elements TU′ shown in  FIG. 2  that are accordingly arranged at fringes of the touch panel TP. In other words, electrode units in the touch-sensing element TU′ are fringe electrodes. As shown in  FIG. 3 , the touch-sensing elements TU are staggered in order to thereby form a rectangular pattern, first electrodes  110  on the same row are series-connected as a sensing trace, and second electrodes  120  on the same column are series-connected as a sensing trace. In addition, two ends of each sensing trace formed by series-connected first electrodes  110  are coupled to the corresponding electrode units  210  on the touch-sensing element TU′, and two ends of each sensing trace formed by series-connected second electrodes  120  are coupled to the corresponding electrode units  220  on the touch-sensing element TU′. In this way, the touch panel TP′ would have a plurality of transverse sensing traces T 1 ′-TN′ and a plurality of longitudinal sensing traces S 1 ′-SM′. Those skilled in the art should readily understand operations of the touch panel TP′ in  FIG. 3  after reading the above mentioned paragraph directed to the electrode unit  200 . Hence, detailed descriptions and modifications may be referred to the above and therefore omitted here for brevity. 
     To sum up, according to the present invention, the electrode unit  200  may increase contact areas arranged for inducting the inductive capacitance C by increasing the perimeter of the sensing pattern formed by the first electrode  210  and the second electrode  220 , so as to increase the value of the inductive capacitance C sensed by the touch-sensing element located on the fringes of the touch panel, and thus may decrease the likelihood of faulty calculation of contact on the fringes of the touch panel. 
     Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.