Patent ID: 9158423
Filing Date: 2015-10-13
Classification: G06F

Abstract:
1. A method for detecting presence of an interference source to be performed by a touch sensing system that stores a threshold capacitance difference, said method comprising the steps of: a) sensing a capacitance at every predetermined unit time interval within a predetermined time duration starting from a first time point and ending at a second time point for obtaining sampled capacitance values; b) obtaining a base capacitance value according to the sampled capacitance values obtained in step a); c) sensing a capacitance at a third time point after the second time point for obtaining a first comparison capacitance value; d) computing a first absolute difference between the first comparison capacitance value obtained in step c) and the base capacitance value obtained in step b); and e) determining that the interference source is present when the first comparison capacitance value is smaller than the base capacitance value and the first absolute difference is greater than the threshold capacitance difference; said method further comprising: when the interference source is determined to be not present in step e), obtaining an updated value of the base capacitance value according to the capacitances sensed during a time period that has the predetermined time duration and that ends at the third time point, and sensing a capacitance at a fourth time point after the third time point for obtaining an updated value of the first comparison capacitance value; and repeating steps d) and e) using the updated values of the base capacitance value and the first comparison capacitance value.