Touch detection techniques for capacitive touch sense systems
First Claim
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1. A method, comprising:
- measuring capacitance values of a capacitance sense element;
analyzing the measured capacitance values to determine a baseline capacitance value for the capacitance sense element;
monitoring a rate of change of the measured capacitance values; and
rejecting an activation of the capacitance sense element as a non-touch event if conditions indicative of the non-touch event are sensed, wherein the conditions indicative of the non-touch event comprise the rate of change of the measured capacitance values having a magnitude greater than a threshold level, wherein the threshold level is indicative of a maximum rate of change of a touch event.
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Abstract
A technique for recognizing and rejecting false activation events related to a capacitance sense interface includes measuring a capacitance value of a capacitance sense element. The measured capacitance value is analyzed to determine a baseline capacitance value for the capacitance sensor. The capacitance sense interface monitors a rate of change of the measured capacitance values and rejects an activation of the capacitance sense element as a non-touch event when the rate of change of the measured capacitance values have a magnitude greater than a threshold level, indicative of a maximum rate of change of a touch event.
370 Citations
14 Claims
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1. A method, comprising:
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measuring capacitance values of a capacitance sense element; analyzing the measured capacitance values to determine a baseline capacitance value for the capacitance sense element; monitoring a rate of change of the measured capacitance values; and rejecting an activation of the capacitance sense element as a non-touch event if conditions indicative of the non-touch event are sensed, wherein the conditions indicative of the non-touch event comprise the rate of change of the measured capacitance values having a magnitude greater than a threshold level, wherein the threshold level is indicative of a maximum rate of change of a touch event. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. An apparatus, comprising:
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a capacitance sense interface including a capacitance sense element having a baseline capacitance value associated with the capacitance sense element; a capacitance measurement circuit coupled to the capacitance sense interface to measure capacitance values of the capacitance sense element and output signal indicative of the measured capacitance values; and event logic coupled to analyze the signals to monitor a rate of change of the measured capacitance values and to reject an activation of the capacitance sense element as a non-touch event if conditions indicative of the non-touch event are sensed, wherein the conditions indicative of the non-touch event comprise the rate of change of the measured capacitance values having a magnitude greater than a threshold level, wherein the threshold level is indicative of a maximum rate of change of a touch event. - View Dependent Claims (12, 13, 14)
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Specification