Patent ID: 6545614
Filing Date: 2003-04-08
Classification: H03K

Abstract:
A touch sensor for sensing a touch of a body part, comprising:an oscillator which outputs a high-frequency signal; an electrode unit comprising a pair of electrodes which applies said high-frequency signal from said oscillator unit to the body part; a detector unit which detects a variety of impedance value varied by said body part contacting said pair of electrodes, and outputs an output signal based on said variety of impedance values; and a discriminator unit which determines whether said body part is in contact with said pair of electrodes by comparing said output signal from said detector unit with a predetermined reference value, wherein a capacitance between the body part and said pair of electrodes increases when the body part is in contact with said pair of electrodes, and a total resistance value of a high-frequency impedance real value of the part of the body part and a circuit resistance value including said pair of electrodes matches an output impedance at a predetermined frequency of said oscillator, allowing said discriminator unit to determine that the contact is that of the body part.