Low power detection on capacitive touch screens

Abstract

This paper presents a novel, power efficient and low-latency method for detecting touch locations on capacitive touch screens. In capacitive touch screens, only a few touch sensors experience detectable change corresponding to the touch locations. We show that power consumption can be reduced by monitoring fewer number of samples than the standard method to sense changes in capacitances and their locations. The proposed method uses group testing for touch sensing and location detection. We also propose a decoding method based on Tikhonov regularization, and provide a closed form of the numerical solution. To verify the proposed method, we compare detection performance and power consumption with those of traditional approach. The results show that the proposed alternative leads to equivalent detection performance with significant reduction in power consumption and sensing latency.