DISPLAY GUARDING TECHNIQUES
First Claim
1. An input device comprising:
- a plurality of sensor electrodes that establish a sensing region of the input device;
at least one display electrode configured to, during display updating, set a voltage associated with a pixel of a display device; and
processing system coupled to the plurality of sensor electrodes and the at least one display electrode, the processing system is configured to;
drive a modulated signal onto a first sensor electrode of the plurality of sensor electrodes to acquire a change in capacitive coupling between an input object and the first sensor electrode during a first period, anddrive a guarding signal onto the at least one display electrode to mitigate an effect of a coupling capacitance between the first sensor electrode and the at least one display electrode during the first period,wherein the modulated signal and the guarding signal have a similar characteristic such that a voltage difference between the first sensor electrode and the first display electrode remains constant during the first period.
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Accused Products
Abstract
Embodiments described herein mitigate the effect of a coupling capacitance between a sensor electrode in a touch sensor and a display electrode in a display screen. An input device, which includes the touch sensor and display screen, may transmit a guarding signal on the display electrodes when performing capacitive sensing. In one embodiment, the guarding signal may have similar characteristics as a modulated signal (e.g., similar amplitude and/or phase) driven on the sensor electrode to detect interaction between the input device and an input object. By driving a guarding signal that is similar to the modulated signal onto the display electrodes, the voltage difference between the sensor electrode and display electrode remains the same. Accordingly, the coupling capacitance between the sensor electrode and the display electrode does not affect a capacitance measurement used to detect the user interaction.
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Citations
30 Claims
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1. An input device comprising:
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a plurality of sensor electrodes that establish a sensing region of the input device; at least one display electrode configured to, during display updating, set a voltage associated with a pixel of a display device; and processing system coupled to the plurality of sensor electrodes and the at least one display electrode, the processing system is configured to; drive a modulated signal onto a first sensor electrode of the plurality of sensor electrodes to acquire a change in capacitive coupling between an input object and the first sensor electrode during a first period, and drive a guarding signal onto the at least one display electrode to mitigate an effect of a coupling capacitance between the first sensor electrode and the at least one display electrode during the first period, wherein the modulated signal and the guarding signal have a similar characteristic such that a voltage difference between the first sensor electrode and the first display electrode remains constant during the first period. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A method for mitigating an effect of a coupling capacitance associated with a display electrode when performing capacitive sensing, the method comprising:
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driving a modulated signal onto a first sensor electrode of a plurality of sensor electrodes to detect a change in capacitive coupling between an input object and the first sensor electrode during a first period; and driving a guarding signal onto the display electrode to mitigate the effect of the coupling capacitance between the first sensor electrode and the display electrode during the first period, wherein the modulated signal and guarding signal have a similar characteristic such that a voltage difference between the first sensor electrode and the display electrode remains constant during the first period. - View Dependent Claims (19, 20, 21, 22, 23)
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24. A processing system for an input device comprising:
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a display driver module comprising display driver circuitry coupled to at least one display electrode and configured to; drive the at least one display electrode to set a voltage associated with a pixel of a display device, and drive a guarding signal onto the at least one display electrode to mitigate the effect of the coupling capacitance between a first sensor electrode of a plurality of sensor electrodes and the at least one display electrode during a first time period and wherein, during the first time period, the first sensor electrode is driven with a modulated signal to detect a change in capacitance between the first sensor electrode and an input object, wherein the modulated signal and the guarding signal have a similar characteristic such that a voltage difference between the first sensor electrode and the at least one display electrode remains constant during the first period. - View Dependent Claims (25, 26, 27, 28)
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29. A processing system for an input device comprising:
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a sensor module comprises sensor circuitry and is coupled to a plurality of sensor electrodes, the sensor module is configured to drive, during a first time period, one of the plurality of sensor electrodes with a modulated signal to detect a change in capacitive coupling between the one sensor electrode and an input object, wherein the sensor module is coupled to and synchronized with a display driver module that is configured to; drive a guarding signal onto at least one display electrode to mitigate the effect of a coupling capacitance between the one sensor electrode and the at least one display electrode during the first time period, wherein the modulated signal and the guarding signal have a similar characteristic such that a voltage difference between the one sensor electrode and the at least one display electrode remains constant during the first period. - View Dependent Claims (30)
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Specification