Patent ID: 7154393
Filing Date: 2006-12-26
Classification: H03K

Abstract:
1. An object detection sensor comprising: a supporting member made from an insulating material; a detection electrode disposed on an inner surface of the supporting member; a touch electrode which is disposed on an outer surface of the supporting member at a position opposed to the detection electrode and capacitance-coupled to the detection electrode; and a detection circuit which is connected to the detection electrode and detects a contact of an object with the touch electrode based on a change in electrostatic capacitance between the detection electrode and the ground and to output a detection signal, wherein a difference correction detection electrode is disposed at a position which is on a periphery of the detection electrode and on the inner surface of the supporting member, and the detection circuit operates a difference between a value corresponding to the electrostatic capacitance between the detection electrode and the ground and a value corresponding to electrostatic capacitance between the difference correction detection electrode and the ground so as to detect a contact of an object with the touch electrode based on the change in the difference and to output a detection signal.