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POINTER DETECTION APPARATUS AND POINTER DETECTION METHOD

  • US 20100321333A1
  • Filed: 03/25/2010
  • Published: 12/23/2010
  • Est. Priority Date: 06/18/2009
  • Status: Active Grant
First Claim
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1. A pointer detection apparatus, comprising:

  • (a) a conductor pattern including a plurality of first conductors disposed in a first direction and a plurality of second conductors disposed in a second direction which crosses the first direction;

    (b) a code string signal production circuit configured to produce a plurality of signals based on a plurality of code strings, each having the same code string and a phase different from each other;

    (c) a transmission conductor selection circuit configured to selectively supply the plurality of signals produced by the code string signal production circuit to the plurality of first conductors, so as to supply each of the plurality of signals to at least two of the first conductors;

    (d) a reception conductor selection circuit configured to selectively receive signals from the plurality of second conductors generated in response to the plurality of signals supplied to the plurality of first conductors;

    (e) a signal detection circuit configured to detect a signal corresponding to a variation of capacitance between the conductor pattern and a pointer, based on the signals from the plurality of second conductors received via the reception conductor selection circuit;

    (f) an analog to digital conversion circuit configured to convert the signal output from the signal detection circuit into a digital signal comprising a word string formed of a plurality of bits;

    (g) a correlation detection circuit configured to determine correlation values between a plurality of code strings provided for correlation and the digital signal comprising a word string formed of a plurality of bits output from the analog to digital conversion circuit;

    (h) a memory circuit configured to store the correlation values successively output from the correlation detection circuit; and

    (i) a position calculation circuit configured to calculate a position on the conductor pattern pointed to by the pointer based on the correlation values.

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