Method and system for detecting multiple touches on a touch-sensitive screen
First Claim
1. A method for indicating that a set of simultaneous contact points on a touch-sensitive screen contains a plurality of contact points, the method comprising:
- setting a multiple contact point discrimination threshold;
at locations along a first edge of the touch-sensitive screen, sending probes across the touch-sensitive screen;
at locations along a second edge of the touch-sensitive screen, attempting to detect probes sent across the touch-sensitive screen, the second edge being across the touch-sensitive screen from the first edge;
of a set of locations along the second edge where attempts to detect probes fail to detect a probe or that detect a probe in an altered state, storing a first location in the set that is at least as close to a third edge of the touch-sensitive screen as any other location in the set, and storing a second location in the set that is at least as close to a fourth edge of the touch-sensitive screen as any other location in the set, the third and fourth edges each being adjacent to the first and second edges;
comparing the multiple contact point discrimination threshold with a distance between the first and second locations; and
if the distance between the first and second locations is greater than the multiple contact point discrimination threshold, then indicating that the set of simultaneous contact points contains a plurality of contact points.
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Accused Products
Abstract
Disclosed are a method and a system for detecting multiple, simultaneous touches on a touch-sensitive screen of a computing device. The hardware that controls the touch screen performs two measurements to locate a touch location on the screen. If there is a single touch, then the two measurements are equal. A non-zero difference indicates multiple touches and is correlated with the spread of locations simultaneously touched on the screen. If the difference is greater than a set threshold, then an indication is given of multiple touches. The user is warned against multiple touches, and input from the screen is ignored as long as multiple touches are detected. For some embodiments, when multiple touches are detected, the invention also tries to indicate the boundary of the set of locations simultaneously touched. The boundary is used to interpolate the intended single touch from the locations of all the touches.
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Citations
26 Claims
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1. A method for indicating that a set of simultaneous contact points on a touch-sensitive screen contains a plurality of contact points, the method comprising:
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setting a multiple contact point discrimination threshold; at locations along a first edge of the touch-sensitive screen, sending probes across the touch-sensitive screen; at locations along a second edge of the touch-sensitive screen, attempting to detect probes sent across the touch-sensitive screen, the second edge being across the touch-sensitive screen from the first edge; of a set of locations along the second edge where attempts to detect probes fail to detect a probe or that detect a probe in an altered state, storing a first location in the set that is at least as close to a third edge of the touch-sensitive screen as any other location in the set, and storing a second location in the set that is at least as close to a fourth edge of the touch-sensitive screen as any other location in the set, the third and fourth edges each being adjacent to the first and second edges; comparing the multiple contact point discrimination threshold with a distance between the first and second locations; and if the distance between the first and second locations is greater than the multiple contact point discrimination threshold, then indicating that the set of simultaneous contact points contains a plurality of contact points. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A computer-readable medium containing computer-executable instructions for perorating a method for indicating that a set of simultaneous contact points on a touch-sensitive screen contains a plurality of contact points, the method comprising:
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setting a multiple contact point discrimination threshold; at locations along a first edge of the touch-sensitive screen, sending probes across the touch-sensitive screen; at locations along a second edge of the touch-sensitive screen, attempting to detect probes sent across the touch-sensitive screen, the second edge being across the touch-sensitive screen from the first edge; of a set of locations along the second edge where attempts to detect probes fail to detect a probe or that detect a probe in an altered state, storing a first location in the set that is at least as close to a third edge of the touch-sensitive screen as any other location in the set, and storing a second location in the set that is at least as close to a fourth edge of the touch-sensitive screen as any other location in the set, the third and fourth edges each being adjacent to the first and second edges; comparing the multiple contact point discrimination threshold with a distance between the first and second locations; and if the distance between the first and second locations is greater than the multiple contact point discrimination threshold, then indicating that the set of simultaneous contact points contains a plurality of contact points.
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14. A method for indicating that a set of simultaneous contact points on a touch-sensitive screen contains a plurality of contact points, the method comprising:
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setting a multiple contact point discrimination threshold; at locations along a first edge of the touch-sensitive screen, sending probes across the touch-sensitive screen; at locations along a second edge of the touch-sensitive screen, attempting to detect probes sent across the touch-sensitive screen, the second edge being across the touch-sensitive screen from the first edge; of a set of locations along the second edge where attempts to detect probes fail to detect a probe or that detect a probe in an altered state, storing a first location in the set that is at least as close to a third edge of the touch-sensitive screen as any other location in the set, and storing a second location in the set that is at least as close to a fourth edge of the touch-sensitive screen as any other location in the set, the third and fourth edges each being adjacent to the first and second edges; computing a first distance between the first and second locations; at locations along the third edge, sending probes across the touch-sensitive screen; at locations along the fourth edge, attempting to detect probes sent across the touch-sensitive screen; of a set of locations along the fourth edge where attempts to detect probes fail to detect a probe or that detect a probe in an altered state, storing a third location in the set that is at least as close to the first edge as any other location in the set, and storing a fourth location in the set that is at least as close to the second edge as any other location in the set; computing a second distance between the third and fourth locations; comparing the multiple contact point discrimination threshold with a combination of the first and second distances; and if the combination of the first and second distances is greater than the multiple contact point discrimination threshold, then indicating that the set of simultaneous contact points contains a plurality of contact points. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23)
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24. A computer-readable medium containing computer-executable instructions for performing a method for indicating that a set of simultaneous contact points on a touch-sensitive screen contains a plurality of contact points, the method comprising:
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setting a multiple contact point discrimination threshold; at locations along a first edge of the touch-sensitive screen, sending probes across the touch-sensitive screen; at locations along a second edge of the touch-sensitive screen, attempting to detect probes sent across the touch-sensitive screen, the second edge being across the touch-sensitive screen from the first edge; of a set of locations along the second edge where attempts to detect probes fail to detect a probe or that detect a probe in an altered state, storing a first location in the set that is at least as close to a third edge of the touch-sensitive screen as any other location in the set, and storing a second location in the set that is at least as close to a fourth edge of the touch-sensitive screen as any other location in the set, the third and fourth edges each being adjacent to the first and second edges; computing a first distance between the first and second locations; at locations along the third edge, sending probes across the touch-sensitive screen; at locations along the fourth edge, attempting to detect probes sent across the touch-sensitive screen; of a set of locations along the fourth edge where attempts to detect probes fail to detect a probe or that detect a probe in an altered state, storing a third location in the set that is at least as close to the first edge as any other location in the set, and storing a fourth location in the set that is at least as close to the second edge as any other location in the set; computing a second distance between the third and fourth locations; comparing the multiple contact point discrimination threshold with a combination of the first and second distances; and if the combination of the first and second distances is greater than the multiple contact point discrimination threshold, then indicating that the set of simultaneous contact points contains a plurality of contact points.
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25. A system for indicating that a set of simultaneous contacts points on a touch-sensitive screen contains a plurality of contact points, the touch-sensitive screen comprising first, second, third, and fourth edges, the first edge being across the touch-sensitive screen from the second edge, the third and fourth edges each being adjacent to the first and second edges, the system comprising:
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a multiple contact point discrimination threshold; a transmitter for sending probes from locations along the first edge across the touch-sensitive screen; a detector for detecting probes received along locations on the second edge; a memory for storing a first location and a second location from a set of locations along the second edge where attempts to detect probes fail to detect a probe or that detect a probe in an altered state, the first location being at least as close to the third edge as any other location in the set, the second location being at least as close to the fourth edge as any other location in the set; a comparator for comparing the multiple contact point discrimination threshold with a distance between the first and second locations; and an indicator for indicating that the set of simultaneous contacts points on the touch-sensitive screen contains a plurality of contact points, the indicator set based on an output of the comparator.
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26. A system for indicating that a set of simultaneous contacts points on a touch-sensitive screen contains a plurality of contact points, the touch-sensitive screen comprising first, second, third, and fourth edges, the first edge being across the touch-sensitive screen from the second edge, the third and fourth edges each being adjacent to the first and second edges, the system comprising:
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a multiple contact point discrimination threshold; a first transmitter for sending probes from locations along the first edge across the touch-sensitive screen; a first detector for detecting probes received along locations on the second edge; a first memory for storing a first location and a second location from a set of locations along the second edge where attempts to detect probes fail to detect a probe or that detect a probe in an altered state, the first location being at least as close to the third edge as any other location in the set, the second location being at least as close to the fourth edge as any other location in the set; a second transmitter for sending probes from locations along the third edge across the touch-sensitive screen; a second detector for detecting probes received along locations on the fourth edge; a second memory for storing a third location and a fourth location from a set of locations along the fourth edge where attempts to detect probes fail to detect a probe or that detect a probe in an altered state, the third location being at least as close to the first edge as any other location in the set, the fourth location being at least as close to the second edge as any other location in the set; a comparator for comparing the multiple contact point discrimination threshold with a combination of a first distance and a second distance, the first distance being a distance between the first location and the second location, the second distance being a distance between the third location and the fourth location; and an indicator for indicating that the set of simultaneous contacts points on the touch-sensitive screen contains a plurality of contact points, the indicator set based on an output of the comparator.
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Specification