31.2: Eliminating Ghost Touches on a Self-Capacitive Touch-Screen



When two or more touches are detected on a self-capacitive touch-screen, positional ambiguities known as “ghost” touches are created.

A novel method of distinguishing between real and “ghost” touches is described. Experimental results for dual-touch give an SNR of over 55 dB, appropriate for secured touch detection in severe environments such as avionics.