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Touch sensor identifying a body part

  • US 6,545,614 B1
  • Filed: 09/28/1999
  • Issued: 04/08/2003
  • Est. Priority Date: 09/28/1998
  • Status: Expired due to Fees
First Claim
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1. 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.

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