Patent Number: 6,310,611

Title: Differential touch sensor and control circuit therefor

Abstract: A differential touch sensor apparatus for detecting the presence of an object such as a human appendage, the apparatus having a first electrode, a second electrode positioned proximate to the first electrode, a differential circuit connected to the first and second electrodes, and a pulse or other signal source connected to provide electrical signals that generate an electric field between the first and second electrodes. Introduction of an object near the first electrode affects the electric field between the first and second electrodes, thereby affecting the voltage difference between them. A differential circuit provides an output signal responsive to the difference in voltage between the first and second electrodes. In an alternative embodiment, a strobe electrode is provided proximate to both said first and second electrodes and the pulses or other signals are provided to the strobe electrode to induce an electric field between the strobe electrode and each of the first and second electrodes.

Inventors: Caldwell; David W. (Winfield, IL)

Assignee: TouchSensor Technologies, LLC

International Classification: H03K 17/94 (20060101); H03K 17/96 (20060101); H03K 17/955 (20060101); G08B 013/24 (); G09G 005/00 ()

Expiration Date: 10/30/2018