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CONTROL UNIT, SENSING DEVICE FOR A CAPACITIVE TOUCH PANEL AND METHOD THEREOF

  • US 20150138152A1
  • Filed: 01/26/2015
  • Published: 05/21/2015
  • Est. Priority Date: 06/24/2009
  • Status: Abandoned Application
First Claim
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1. A sensing device for a capacitive touch panel, the capacitive touch panel being rectangular and having a transparent substrate and a sensing layer on the transparent substrate, the sensing layer being transparent and electrically conductive, the capacitive touch panel further having a first X side, a second X side, a first Y side and a second Y side, the sensing device comprising:

  • a first X side switch circuit connected to the first X side;

    a second X side switch circuit connected to the second X side;

    a first Y side switch circuit connected to the first Y side;

    a second Y side switch circuit connected to the second Y side;

    a sensing source, comprising a first sensing signal source and a second sensing signal source; and

    a control circuit, receiving at least one first sensing signal generated by the first sensing signal source and at least one second sensing signal generated by the second sensing signal source, the control circuit further comprising;

    a first current measurement circuit, receiving a first X side current signal generated by the first X side switch circuit or a first Y side current signal generated by the first Y side switch circuit;

    a second current measurement circuit, receiving a second X side current signal generated by the second X side switch circuit or a second Y side current signal generated by the second Y side switch circuit;

    a first sample and hold circuit, connected to and sampling output of the first current measurement circuit;

    a second sample and hold circuit, connected to and sampling output of the second current measurement circuit;

    a switch, selectively connected to one of outputs of the first sample and hold circuit and the second sample and hold circuit according to the received first sensing signal or the second sensing signal; and

    a control unit, comprising;

    an analogue/digital conversion circuit, connected to the switch to receive a first X side analogue signal generated by the first X side current signal, a first Y side analogue signal generated by the first Y side current signal, a second X side analogue signal generated by the second X side current signal and a second Y side analogue signal generated by the second Y side current signal, and correspondingly converting them into a first X side digital signal, a second X side digital signal, a first Y side digital signal and a second Y side digital signal; and

    a location determining unit, connected to the analogue/digital conversion circuit, and comprising;

    an X coordinate determining device, determining X coordinate of a touch point according to the first X side digital current signal and the second X side digital current signal; and

    an Y coordinate determining device, determining Y coordinate of the touch point according to the first Y side digital current signal and the second Y side digital current signal.

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