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Touch panel

  • US 8,044,943 B2
  • Filed: 06/03/2008
  • Issued: 10/25/2011
  • Est. Priority Date: 06/03/2008
  • Status: Expired due to Fees
First Claim
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1. A touch panel, comprising:

  • a bias line, biased at a bias voltage;

    a select line;

    a readout line;

    a photo cell, comprising;

    a first photo TFT, having a first terminal, a second terminal and a control terminal, wherein the first terminal is coupled to the readout line and the control terminal is coupled to the select line;

    a second photo TFT, having a first terminal, a second terminal and a control terminal, wherein the first terminal is coupled to the readout line, the second terminal and the control terminal are coupled to the bias line; and

    a storage capacitor, coupling the second terminal of the first photo TFT to the bias line;

    a readout circuit comprising;

    an operational amplifier, having an inverting input terminal, a non-inverting input terminal and an output terminal, wherein the inverting input terminal is coupled to the readout line;

    a feedback capacitor, coupled between the inverting input terminal and the output terminal of the operational amplifier; and

    a first switch, coupled between the inverting input terminal and the output terminal of the operational amplifier, anda multiplexer for selectively outputting a reference voltage or the bias voltage to the non-inverting input terminal.

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