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Systems and method for detecting contact with a display panel by asymetric detection waveform

  • US 9,046,968 B2
  • Filed: 06/04/2010
  • Issued: 06/02/2015
  • Est. Priority Date: 06/29/2009
  • Status: Active Grant
First Claim
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1. A capacitance-type touch panel comprising:

  • a plurality of drive electrodes each having a strip shape;

    a drive control circuit performing control such that a drive signal for touch detection is selectively applied to the drive electrodes;

    a plurality of touch detection electrodes arranged to intersect with the drive electrodes in such a manner that capacitance is formed in each intersecting part, and each outputting a detection signal in synchronization with the drive signal; and

    a detection circuit detecting an external proximity object based on the detection signal,wherein the drive control circuit controls application of the drive signal such that a positive drive signal is selectively applied to predetermined regions of the display in a first period;

    a negative drive signal is applied to predetermined regions of the display in a second period different from the first period so that there is a difference in surface area of the drive electrodes receiving the positive and negative drive signals for contact detection thereby causing a time-average level of the detection signal both in the first period and the second period to be shifted with respect to a center voltage of the detection signal when a portion of the display is contacted or approached due to a difference in capacitance between the first period and the second period; and

    the detection circuit detects the external proximity object based on a shift of the time-average level of the detection signal both in the first period and the second period with respect to the center voltage of the detection signal.

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