System and method for locating a touch on a capacitive touch screen
First Claim
1. A capacitive touch sensor comprising:
- a sensor array including a first plurality of lead lines and a series of sensor bars, the number of sensor bars in the series of sensor bars exceeding the number of lead lines in the first plurality of lead lines, the sensor bars each comprising a first end and a second end, the first end of each sensor bar being connected to one of the first plurality of lead lines, the series of sensor bars being further divided into windows of sensor bars with each window of sensor bars having a corresponding set of lead lines from the first plurality of lead lines, wherein each set of lead lines is distinguishable from each other set of lead lines such that each window of sensor bars is distinguishable from each other window of sensor bars, and wherein distinguishing one window of sensor bars from another window of sensor bars is based on identifying a set of signals present on an identified set of lead lines and comparing the identified set of lead lines to a listing of possible sets of lead lines to determine a matching set of lead lines, wherein the identified set of lead lines only has one possible matching set of lead lines in the listing of possible sets of lead lines.
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Abstract
Described is a touch-sensitive screen having a sensing circuit capable of discriminating where a perturbation of an electric field created by the sensing circuit occurs. The invention may be implemented in a capacitive touch sensor in which each of multiple conductive sensor bars is connected to a conductive lead line. There are fewer lead lines than sensor bars. Thus, at least one and likely several lead lines are connected to more than one sensor bar. The particular connections of lead lines to sensor bars are selected to avoid ambiguity created by a given signal being possibly generated on more than a single conductive bar. More specifically, the invention provides a technique for laying out lead line to sensor bar connections to enable distinguishing which sensor bar, having common lead lines with other sensor bars, has experienced or is closest to a touch on the sensor.
157 Citations
17 Claims
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1. A capacitive touch sensor comprising:
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a sensor array including a first plurality of lead lines and a series of sensor bars, the number of sensor bars in the series of sensor bars exceeding the number of lead lines in the first plurality of lead lines, the sensor bars each comprising a first end and a second end, the first end of each sensor bar being connected to one of the first plurality of lead lines, the series of sensor bars being further divided into windows of sensor bars with each window of sensor bars having a corresponding set of lead lines from the first plurality of lead lines, wherein each set of lead lines is distinguishable from each other set of lead lines such that each window of sensor bars is distinguishable from each other window of sensor bars, and wherein distinguishing one window of sensor bars from another window of sensor bars is based on identifying a set of signals present on an identified set of lead lines and comparing the identified set of lead lines to a listing of possible sets of lead lines to determine a matching set of lead lines, wherein the identified set of lead lines only has one possible matching set of lead lines in the listing of possible sets of lead lines. - View Dependent Claims (2, 3, 4, 5, 6, 7)
a second plurality of lead lines equaling the number of the first plurality of lead lines so that each of the first plurality of lead lines has a corresponding lead line in the second plurality of lead lines, the second plurality of lead lines being connected to the second ends of the sensor bars so that each sensor bar is connected to one of the first plurality of lead lines and the corresponding one of the second plurality of lead lines.
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8. A capacitive touch sensor comprising:
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a sensor array comprising a plurality of lead lines and a series of sensor bars, the sensor array having a first side and a second side, the plurality of lead lines being divided equally between the first side and the second side, the series of sensor bars being further divided into windows of sensor bars with each of the windows of sensor bars having a corresponding set of lead lines from the plurality of lead lines, wherein a first set of lead lines is distinguishable from each other set of lead lines such that each window of sensor bars is distinguishable from each other window of sensor bars, wherein the first set of lead lines is uniquely distinguishable from each other set of lead lines due to a signal pattern generated from a touch to the window of sensor bars corresponding to the first set of lead lines being distinguishable from another signal pattern generated by a touch to any other window of sensor bars.
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9. A capacitive touch sensor comprising:
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a sensor array comprising a plurality of lead lines and a series of sensor bars, the sensor array having a first side and a second side, the plurality of lead lines being divided equally between the first side and the second side, the series of sensor bars being further divided into windows of sensor bars with each of the windows of sensor bars having a corresponding set of lead lines from the plurality of lead lines, wherein a first set of lead lines is distinguishable from each other set of lead lines such that each window of sensor bars is distinguishable from each other window of sensor bars, wherein the first set of lead lines does not include the same lead lines as any other set of lead lines.
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10. A capacitive touch sensor comprising:
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a sensor array comprising a plurality of lead lines and a series of sensor bars, the sensor array having a first side and a second side, the plurality of lead lines being divided equally between the first side and the second side, the series of sensor bars being further divided into windows of sensor bars with each of the windows of sensor bars having a corresponding set of lead lines from the plurality of lead lines, wherein a first set of lead lines is distinguishable from each other set of lead lines such that each window of sensor bars is distinguishable from each other window of sensor bars, wherein the first set of lead lines includes the same lead lines as another set of lead lines but in a different arrangement.
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11. A method for identifying a location of a touch on a sensor screen, comprising:
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identifying a set of signals present on a set of lead lines connected to sensor bars on the sensor screen;
determining whether the set of lead lines corresponds to an existing window of sensor bars within a plurality of windows of sensor bars on the sensor screen, wherein each window of sensor bars has a corresponding set of lead lines; and
if the set of lead lines corresponds to an existing window of sensor bars, identifying the corresponding window as the location of the touch, wherein determining whether the set of lead lines corresponds to an existing window comprises assigning an initial order to the set of lead lines and comparing the initial order to a listing of existing orders of existing sets of lead lines to identify a match. - View Dependent Claims (12, 13, 14, 15, 16, 17)
if no match is identified with the initial order, iteratively reordering the set of lead lines and repeating the comparison with the new orders until the match is identified.
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13. The method of claim 12, wherein if no match is found, indicating that an error has occurred.
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14. The method of claim 11, wherein the existing orders of existing sets of lead lines are each distinguishable from one another.
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15. The method of claim 11, wherein determining whether the set of lead lines corresponds to an existing window comprises determining if the set of signals present on the set of lead lines forms a bump pattern consistent with a bump pattern possible by a touch on the existing window.
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16. The method of claim 11, wherein determining whether the set of lead lines corresponds to an existing window comprises determining if the set of signals present on the set of lead lines forms an ascending pattern consistent with an ascending pattern possible by a touch on the existing window.
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17. The method of claim 11, wherein determining whether the set of lead lines corresponds to an existing window comprises determining if the set of signals present on the set of lead lines forms a descending pattern consistent with a descending pattern possible by a touch on the existing window.
Specification