CHIRP SIGNAL TOUCH SENSOR
First Claim
Patent Images
1. An apparatus comprising:
- a signal generator operable to generate an electric signal having a frequency that varies in time;
a drive electrode of a touch sensor operable to be stimulated by the electric signal;
a sense electrode of a touch sensor capacitatively coupled to the drive electrode;
a detector electrically coupled to the sense electrode and operable to perform a measurement associated with the sense electrode; and
a controller operable to determine whether a touch on the touch sensor occurred by determining whether the measurement deviates from an expected value by more than an amount.
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Abstract
In one embodiment, an apparatus includes a drive electrode, a sense electrode, a detector, and a controller. The drive electrode is stimulated by an electric signal that has a frequency that varies in time. The sense electrode is capacitatively coupled to the drive electrode. The detector performs a measurement associated with the sense electrode. The controller determines whether a touch on the touch sensor occurred by determining whether the measurement deviates from an expected value by more than an amount.
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Citations
20 Claims
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1. An apparatus comprising:
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a signal generator operable to generate an electric signal having a frequency that varies in time; a drive electrode of a touch sensor operable to be stimulated by the electric signal; a sense electrode of a touch sensor capacitatively coupled to the drive electrode; a detector electrically coupled to the sense electrode and operable to perform a measurement associated with the sense electrode; and a controller operable to determine whether a touch on the touch sensor occurred by determining whether the measurement deviates from an expected value by more than an amount. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method comprising:
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generating, by a signal generator, an electric signal having a frequency that varies in time; stimulating a drive electrode of a touch sensor with the electric signal; performing, by a detector, a measurement associated with a sense electrode capacitatively coupled to the drive electrode; determining, by a controller, whether a touch occurred in response to a determination whether the measurement deviated from an expected value by an amount.
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- 9. The method of claim 9 further comprising the step of varying a variable pass band associated with a filter in order to pass the frequency of the electric signal.
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12. The method of claim 12, wherein the amplitude of the electric signal is greatest when the frequency of the electric signal is a harmonic of the frequency of the noise signal.
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14. A system comprising:
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a generator element operable to generate an electric signal having a frequency that varies in time; a drive element operable to be stimulated by the electric signal; a sense element capacitatively coupled to the drive element; a detecting element electrically coupled to the sense element and operable to perform a measurement associated with the sense element; and a control element operable to determine whether a touch occurred by determining whether the measurement deviates from an expected value by more than an amount. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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Specification