Touch sensor with adaptive touch detection thresholding

  • US 9,411,472 B2
  • Filed: 12/08/2011
  • Issued: 08/09/2016
  • Est. Priority Date: 12/08/2011
  • Status: Active Grant
First Claim
Patent Images

1. A touch sensor comprising:

  • a plurality of sense electrodes; and

    a controller communicatively coupled to the plurality of sense electrodes, the controller configured to;

    receive a plurality of signals from the plurality of sense electrodes associated with an interaction with the touch sensor by an external object, the plurality of signals indicative of an amount of capacitance between the touch sensor and the external object;

    access a stored threshold value, the threshold value indicating a threshold magnitude of capacitance;

    determine a grounding status of the touch sensor based on a strength of a charge return path between the touch sensor and a ground;

    adjust the stored threshold value based on the determined grounding status of the touch sensor;

    after adjusting the stored threshold value, determine whether to process the interaction as a touch by the external object based on a comparison of the amount of capacitance with the adjusted threshold value; and

    after adjusting the stored threshold value based on the determined grounding status of the touch sensor;

    determine that the external object has not touched the touch sensor within a predetermined amount of time; and

    change the stored threshold value back to an original value, the original value comprising a value of the stored threshold value before it was adjusted based on the determined grounding status of the touch sensor.

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