Abstract:
This invention provides a system for scanning control of a capacitive touch panel. The system includes a driving unit driving a partially neighboring strips of a plurality of first axial conductive strips of the capacitive touch panel, wherein the plurality of first axial conductive strips are parallel to each other, and a first detecting unit detecting one of the partially neighboring strips of first axial conductive strips. By doing so, the influence caused by unintended conducting materials can be kept from the touch point detection for the capacitive touch panel, and the electro-magnetic interference of the capacitive touch panel can be also decreased.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part of co-pending application Ser. No. 11/519,094, filed Sep. 12, 2006. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention generally relates to the field of touch panel, and more particularly, to a system and method for scanning control of a capacitive touch panel. 
     2. Description of the Prior Art 
     Most people often use electronic devices equipped with touch-controlled displays in their daily lives, for example an automated teller machine or a copy machine. By slightly touching icons shown on the display, a user can easily operate the desired functions. The touch-controlled operation is provided by a transparent touch panel mounted on the surface of the display. The touch panels can be categorized to resistive type, capacitive type, and surface wave type. When putting a finger on the resistive touch panel, a voltage signal occurs for calculating coordinate information of the touch point. For the capacitive touch panel, the coordinate information is obtained based on variations of electrical current since a user&#39;s finger can absorb a minor current when touching the panel. 
     Referring to  FIG. 1 , a schematic diagram for a well-known driving/detecting control system  100  of a capacitive touch panel is illustrated. A capacitive touch panel  110  has m first axial conductive strips X 0 -X m-1 , each of which being parallel with each other, and also has n second axial conductive strips Y 0 -Y n-1 , each of which being parallel with each other, wherein m≧3, n≧3, and m, n are natural number. Herein, the m first axial conductive strips X 0 -X m-1  intersect the n second axial conductive strips Y 0 -Y n-1  with electrical isolation. A driving/detecting unit  120  is adapted to drive and detect the m first axial and the n second axial conductive strips X 0 -X m-1  and Y 0 -Y n-1 . In one embodiment, for example, the driving/detecting unit  120  drives one first axial conductive strip and detects it, and then repeats the operations to the one next to it until all m first axial conductive strips X 0 -X m-1  being driven and detected. However, when the capacitive touch panel  110  has an unintended conducting material (not shown) on it, such as water or other conducting materials, the equivalent circuit and the equivalent stray capacitance between the axial conductive strips at the unintended conducting material will be changed. This change makes the driving/detecting unit  120  detect the current change or charge change on the axial conductive strips, and then results in misjudgment and mal-operation. Or, when the axial conductive strip related to the touch is provided the driving signal and is detected change in current or charges, the current change or the charge change are affected by the unintended conducting material. That is, those relatively bigger changes of the current or charges are bypassed to the adjacent axial conductive strip to ground through the unintended conducting material. Therefore, the position of the touch cannot be correctly detected. 
     One solution to the abovementioned problem is to drive all same axial conductive strips and then to detect one conductive strip thereof. Since all same axial conductive strips are driven, this makes all same axial conductive strips have the same voltage level. In the meantime, there is no voltage difference among all same axial conductive strips, so there is no current loop among them as well. If an unintended conducting material exists on the capacitive touch panel in the meanwhile, the unintended conducting material will not form current loops with all same axial conductive strips because there is no voltage difference among them. Therefore, the unintended conducting material does not change the current among all same axial conductive strips. However, this solution makes both power consumption and electro-magnetic interference increase. 
     In view of the drawbacks mentioned with the prior art of scanning control of a capacitive panel, there is a continuous need to develop a new and improved system and method for scanning control of a capacitive panel that overcomes the shortages associated with the prior art. The advantages of the present invention are that it solves the problems mentioned above. 
     SUMMARY OF THE INVENTION 
     In accordance with the present invention, a system and method for scanning control of a capacitive touch panel substantially obviates one or more of the problems resulted from the limitations and disadvantages of the prior art mentioned in the background. 
     The present invention provides a system for scanning control of a capacitive touch panel. The system includes a driving unit driving a partially neighboring strips of a plurality of first axial conductive strips of the capacitive touch panel at the same time, wherein the plurality of first axial conductive strips are parallel to each other, and a first detecting unit detecting one of the partially neighboring strips of first axial conductive strips. By doing so, the influence caused by unintended conducting materials can be kept from the touch point detection for the capacitive touch panel, and the electro-magnetic interference of the capacitive touch panel can be also decreased. 
     In an alternate preferred embodiment, the driving unit further drives a partially neighboring strips of a plurality of second axial conductive strips of the capacitive touch panel at the same time, wherein the plurality of second axial conductive strips are parallel to each other and intersect with the plurality of first axial conductive strips with electrical isolation, and a second detecting unit detects one of the partially neighboring strips of second axial conductive strips. 
     The present invention provides a method for scanning control of a capacitive touch panel. The method includes driving a partially neighboring strips of a plurality of first axial conductive strips of the capacitive touch panel simultaneously by a driving unit, wherein the plurality of first axial conductive strips are parallel to each other, and detecting one of the partially neighboring strips of first axial conductive strips by a first detecting unit. By doing so, the influence caused by unintended conducting materials can be kept from the touch point detection for the capacitive touch panel, and the electro-magnetic interference of the capacitive touch panel can be also decreased. 
     In an alternate preferred embodiment, the method further includes driving a partially neighboring strips of a plurality of second axial conductive strips of the capacitive touch panel simultaneously by the driving unit, wherein the plurality of second axial conductive strips are parallel to each other and intersect with the plurality of first axial conductive strips with electrical isolation, and detecting one of the partially neighboring strips of second axial conductive strips by a second detecting unit. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings incorporated in and forming a part of the specification illustrate several aspects of the present invention, and together with the description serve to explain the principles of the disclosure. In the drawings: 
         FIG. 1  shows a well-known driving/detecting control system for a capacitive touch panel; 
         FIG. 2A  depicts one preferred embodiment in accordance with the present invention; 
         FIG. 2B  depicts another preferred embodiment in accordance with the present invention; 
         FIG. 3A  illustrates a flow chart for one preferred embodiment in accordance with the present invention; and 
         FIG. 3B  illustrates a flow chart for another preferred embodiment in accordance with the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Some embodiments of the present invention will now be described in greater detail. Nevertheless, it should be noted that the present invention can be practiced in a wide range of other embodiments besides those explicitly described, and the scope of the present invention is expressly not limited except as specified in the accompanying claims. 
     Moreover, some irrelevant details are not drawn in order to make the illustrations concise and to provide a clear description for easily understanding the present invention. 
     Referring to  FIG. 2A , a schematic diagram for one preferred embodiment  200  in accordance with the present invention is depicted. A capacitive touch panel  205  has m first axial conductive strips X 0 -X m-1 , each of which being parallel with each other, wherein m≧3 and m is natural number. The capacitive touch panel  205  also has n second axial conductive strips Y 0 -Y n-1 , each of which being parallel with each other, wherein n≧3 and n is natural number. Herein, the m first axial conductive strips X 0 -X m-1  intersect the n second axial conductive strips Y 0 -Y n-1  with electrical isolation. A driving unit  210  simultaneously drives a partially neighboring strips of m first axial conductive strips X 0 -X m-1  in sequence or in interleaving or by assigned until all m first axial conductive strips X 0 -X m-1  being detected over by a detecting unit  220 . Herein, the partially neighboring strips of m first axial conductive strips X 0 -X m-1  include 3-7 first axial conductive strips. For example, the driving unit  210  drives r first axial conductive strip(s), X s , and s first axial conductive strip(s) at the same time, herein 1≦r≦3, 1≦s≦3 and r, s are natural number. The detecting unit  220  detects one of the partially neighboring strips of first axial conductive strips driven by the driving unit  210 . In one preferred case, the one (e.g. X s ) of the partially neighboring strips of first axial conductive strips positions at the middle of the partially neighboring strips of first axial conductive strips, but not limit to. In some cases, the one of the partially neighboring strips of first axial conductive strips could not position at the middle of the partially neighboring strips of first axial conductive strips. 
     Similarly, the operations for the driving unit  210  and the detecting unit  220  to the n second axial conductive strips Y 0 -Y n-1  are similar to those descriptions mentioned above to the m first axial conductive strips X 0 -X m-1 . For example, the driving unit  210  drives p second axial conductive strip(s), Y s , and q second axial conductive strip(s) at the same time, herein 1≦p≦3, 1≦q≦3 and p, q are natural number. For example, in one preferred case, the one (e.g. Y s ) of the partially neighboring strips of second axial conductive strips positions at the middle of the partially neighboring strips of second axial conductive strips, but in some cases, the one of the partially neighboring strips of second axial conductive strips could not position at the middle of the partially neighboring strips of second axial conductive strips. 
     A signal processing unit  230  processes a first data receiving from the detecting unit  220 . A control unit  240  receives a second data from the signal processing unit  230  and controls the driving unit  210  and the detecting unit  220 . Herein, the first data is translated into the second data by filtering, sampling, amplifying, and analog-to-digital converting. 
     In accordance with another aspect of the present invention, a plurality of detecting units can be adapted to detect a correspondingly partial of the same axial conductive strips, which are next to each other, For example, a first detecting unit is in charge of X 0 -X 127 , a second detecting unit is in charge of X 128 -X 255 , a third detecting unit is in charge of X 256 -X 383 , and so forth, for speeding up detection. And then, one or multiple switching unit(s) is(are) used to switch and receive data from the plurality of detecting units. However, the plurality of detecting units may still have different electronic characteristics although they are composed of the same circuit and electronic elements. Accordingly, this makes the data slightly different from different detecting units. For example, a first detecting unit detects a charge on X 0  being smaller than a threshold but the charge on X 0  would be higher than the threshold if it is detected by a second detecting unit. That is, the plurality of detecting unit for the detection of the same axial conductive strip are lack of a regulation among them and hence make the detection error easily. Moreover, the plurality of detecting units also get different decay rate after a period of use, and this makes the problem mentioned above more serious. As for the present invention, the same axial conductive strips are detected by one detecting unit and further with the same effect resulted from the decay of the detecting unit. Therefore, the problem mentioned above would not occur and be solved in the present invention. 
     Referring to  FIG. 2B , a schematic diagram for another preferred embodiment  200 A in accordance with the present invention is depicted. The differences between  FIG. 2A  and  FIG. 2B  are that two detecting units  220 A and  220 B are used to respectively detect the n second axial conductive strips Y 0 -Y n-1  and the m first axial conductive strips X 0 -X m-1 , and that a switching unit  225  is adapted to switch and receive a first data from the two detecting units  220 A and  220 B to the signal processing unit  230 , and the control unit  240 A further controls the two detecting units  220 A and  220 B and the switching unit  225 . However, the operations in  FIG. 2B  are similar to those mentioned in  FIG. 2A , for example, the driving unit  210  drives a partially neighboring strips of m first axial conductive strips X 0 -X m-1  at the same time, and the detecting unit  220 B detects one of the partially neighboring strips of first axial conductive strips; and the driving unit  210  further drives a partially neighboring strips of n second axial conductive strips Y 0 -Y n-1 , and the detecting unit  220 A detects one of the partially neighboring strips of second axial conductive strips. As for the meanings of the denotations shown in  FIG. 2B , such as X s , Y s , p, q, r, and s, are the same as those descriptions in  FIG. 2A , and this part can be figured out by one ordinary skilled in the art according to those descriptions in  FIG. 2A . Thus, no more detail will be described. 
     Referring to  FIG. 3A , a flow chart for one preferred embodiment in accordance with the present invention is illustrated. In step  302 , simultaneously driving a partially neighboring strips of a plurality of first axial conductive strips of a capacitive touch panel by a driving unit. Herein, the plurality of first axial conductive strips are parallel to each other in X-axial (or Y-axial). In step  304 , detecting one of the partially neighboring strips of first axial conductive strips by a first detecting unit. Herein, in one preferred case, the one of the partially neighboring strips of first axial conductive strips positions at the middle of the partially neighboring strips of first axial conductive strips, but not limit to. In some cases, the partially neighboring strips of first axial conductive strips include 3-7 first axial conductive strips. In step  306 , processing a first data receiving from the first detecting unit by a signal processing unit. In step  308 , receiving a second data from the signal processing unit and controlling the driving unit and the first detecting unit by a control unit. Herein, the first data is translated into the second data by including filtering, sampling, amplifying, and analog-to-digital converting. 
     Referring to  FIG. 3B , a flow chart for one preferred embodiment in accordance with the present invention is illustrated. In step  312 , simultaneously driving a partially neighboring strips of a plurality of first axial conductive strips of a capacitive touch panel by a driving unit. Herein, the plurality of first axial conductive strips are parallel to each other in X-axial (or Y-axial). In step  314 , detecting one of the partially neighboring strips of first axial conductive strips by a first detecting unit. Herein, in one preferred case, the one of the partially neighboring strips of first axial conductive strips positions at the middle of the partially neighboring strips of first axial conductive strips, but not limit to. In some cases, the partially neighboring strips of first axial conductive strips include 3-7 first axial conductive strips. In step  322 , simultaneously driving a partially neighboring strips of a plurality of second axial conductive strips of the capacitive touch panel by the driving unit. Herein, the plurality of second axial conductive strips are parallel to each other in Y-axial (or X-axial) and intersect with the plurality of first axial conductive strips with electrical isolation. In step  324 , detecting one of the partially neighboring strips of second axial conductive strips by a second detecting unit. Herein, in one preferred case, the one of the partially neighboring strips of second axial conductive strips positions at the middle of the partially neighboring strips of second axial conductive strips, but not limit to. In some cases, the partially neighboring strips of second axial conductive strips include 3-7 second axial conductive strips. In step  316 , processing a first data receiving from the first and second detecting units through a switching unit by a signal processing unit. In step  318 , receiving a second data from the signal processing unit and controlling the driving unit, the first and second detecting units, and the switching unit by a control unit. Herein, the first data is translated into the second data by including filtering, sampling, amplifying, and analog-to-digital converting 
     Although specific embodiments have been illustrated and described, it will be obvious to those skilled in the art that various modifications may be made without departing from what is intended to be limited solely by the appended claims.