Minimizing mismatch during compensation
AssigneeApple Inc.
InventorsSteve Porter Hotelling, Brian Richards Land
Life of this patent
Estimating the term…
Abstract
A method and apparatus for minimizing mismatch effects between a compensation signal and an output signal generated by a touch surface device is disclosed. In one embodiment the apparatus includes a touch-sensitive panel having a sense node for providing an output signal indicative of a touch or no-touch condition on the panel; a drive circuit for generating a sinusoidal drive signal provided to the sense node of the touch-sensitive panel; at least one non-touch-sensitive node within the touch-sensitive panel, for generating a sinusoidal compensation signal, wherein the sinusoidal compensation signal is summed with the output signal to provide a sinusoidal compensated output signal; and a sensing circuit for receiving the sinusoidal compensated output signal.
Claims34
A touch surface device, comprising:
- a compensation circuit configured for receiving an output signal from a sense node on a touch-sensitive panel, generating a compensation signal, adjusting at least one parameter of the compensation signal based on a location of the sense node on the panel, and combining the compensation signal with the output signal to produce a compensated output signal;
- and
- a demodulator coupled for receiving and demodulating the compensated output signal.
A touch surface device, comprising:
- a touch-sensitive panel having a sense node for providing an output signal indicative of a touch or no-touch condition on the panel;
- a drive circuit for generating a sinusoidal drive signal provided to the sense node of the touch-sensitive panel;
- at least one non-touch-sensitive node within the touch-sensitive panel, for generating a sinusoidal compensation signal, wherein the sinusoidal compensation signal is summed with the output signal to provide a sinusoidal compensated output signal;
- and
- a sensing circuit for receiving the sinusoidal compensated output signal.
A computer system incorporating a touch surface device, comprising:
- a compensation circuit configured for receiving an output signal from a sense node on a touch-sensitive panel, generating a compensation signal, adjusting at least one parameter of the compensation signal based on a location of the sense node on the panel, and combining the compensation signal with the output signal to produce a compensated output signal;
- a demodulator coupled for receiving and demodulating the compensated output signal;
- and
- a processor coupled to receive and process the demodulated compensated output signal and perform one or more functions based on data provided by the compensated output signal.
A computer system incorporating a touch surface device, comprising:
- a touch-sensitive panel having a sense node for providing an output signal indicative of a touch or no-touch condition on the panel;
- a drive circuit for generating a sinusoidal drive signal provided to the sense node of the touch-sensitive panel;
- and
- at least one non-touch-sensitive node within the touch-sensitive panel, for generating a sinusoidal compensation signal, wherein the sinusoidal compensation signal is summed with the output signal to provide a sinusoidal compensated output signal;
- a sensing circuit for receiving the sinusoidal compensated output signal and converting the sinusoidal compensated output signal into a digital signal;
- and
- a processor for receiving and processing the digital signal and perform one or more functions based on the data provided by the digital signal.
A method of minimizing mismatch between an output signal of a touch surface device and a compensation signal, comprising:
- generating an output signal at a sense node of a touch-sensitive panel, wherein the output signal is indicative of a touch or no-touch condition on the panel;
- combining the output signal with a compensation signal to produce a compensated output signal, wherein at least one parameter of the compensation signal is adjusted based on a location of the sense node on the panel;
- and
- demodulating the compensated output signal.
A method of minimizing mismatch between an output signal of a touch surface device and a compensation signal, comprising:
- providing a sinusoidal drive signal to a sense node of a touch-sensitive panel so as to generate an output signal indicative of a touch or no-touch condition on the sense node;
- inverting the sinusoidal drive signal to provide a compensation drive signal;
- and
- providing the compensation drive signal to at least one non-touch-sensitive node within the touch-sensitive panel, for generating a sinusoidal compensation signal, wherein the sinusoidal compensation signal is summed with the output signal to provide a sinusoidal compensated output signal.
A method of minimizing mismatch effects between a compensation signal and an output signal generated by a touch surface device, comprising:
- providing a sinusoidal drive signal to a first electrode of the touch surface device;
- providing a sinusoidal output signal from a second electrode of the touch surface device to a first input of a summing circuit, the sinusoidal output signal being generated due to a mutual capacitance between the first and second electrodes;
- providing a sinusoidal compensation signal to a second input of the summing circuit, wherein the sinusoidal compensation signal is substantially 180 degrees out of phase with the sinusoidal output signal;
- and
- providing a compensated output signal from an output of the summing circuit to an inverting input of an amplifier, wherein a non-inverting input of the amplifier is provided with a substantially constant voltage.
An apparatus for minimizing mismatch between an output signal of a touch surface device and a compensation signal, comprising:
- means for generating an output signal at a sense node of a touch-sensitive panel, wherein the output signal is indicative of a touch or no-touch condition on the panel;
- means for combining the output signal with a compensation signal to produce a compensated output signal, wherein at least one parameter of the compensation signal is adjusted based on a location of the sense node on the panel;
- and
- means for demodulating the compensated output signal.
An apparatus for minimizing mismatch between an output signal of a touch surface device and a compensation signal, comprising:
- means for providing a sinusoidal drive signal to a sense node of a touch-sensitive panel so as to generate an output signal indicative of a touch or no-touch condition on the sense node;
- means for inverting the sinusoidal drive signal to provide a compensation drive signal;
- and
- means for providing the compensation drive signal to at least one non-touch-sensitive node within the touch-sensitive panel, for generating a sinusoidal compensation signal, wherein the sinusoidal compensation signal is summed with the output signal to provide a sinusoidal compensated output signal.
An apparatus for minimizing mismatch effects between a compensation signal and an output signal generated by a touch surface device, comprising:
- means for providing a sinusoidal drive signal to a first electrode of the touch surface device;
- means for providing a sinusoidal output signal from a second electrode of the touch surface device to a first input of a summing circuit, the sinusoidal output signal being generated due to a mutual capacitance between the first and second electrodes;
- means for providing a sinusoidal compensation signal to a second input of the summing circuit, wherein the sinusoidal compensation signal is substantially 180 degrees out of phase with the sinusoidal output signal;
- and
- means for providing a compensated output signal from an output of the summing circuit to an inverting input of an amplifier, wherein a non-inverting input of the amplifier is provided with a substantially constant voltage.
Dependencies are inferred from the claim text.