CAPACITIVE SENSING SYSTEM

摘要

The invention relates to capacitive sensing system (1) for sensing an object. The capacitive sensing system (1) comprises an electrical charge providing unit (4) like an electret foil for providing a permanent electrical charge at a sensing site (6) of the object (3) and a capacitive sensor (2) comprising a sensing electrode (5) for generating a sensing signal by capacitively sensing the object (3) at the sensing site (6) of the object (3). By providing a permanent electrical charge at the sensing site (6) of the object (3), the bias between the object (3) and the sensing electrode (5) of the capacitive sensor (2) is intentionally preferentially made large, thereby increasing the sensitivity towards mechanical motions. The resulting sensing signal substantially caused by these mechanical motions between the object (3) and the sensing electrode (5) is generally larger than a signal generated substantially by an electrophysiological field.