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US 8,773,146 B1Granted
Waterproof scanning of a capacitive sense array
AssigneeCypress Semiconductor Corporation
InventorsMichael Patrick Hills, Volodymyr Burkovskyy, Oleksandr Karpin, Seok Pyong Park, Patrick Prendergast
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Abstract
A water-resistant capacitance sensing apparatus comprising a plurality of capacitive sense elements and a capacitance sensing circuit configured to measure both the mutual capacitance and self-capacitance on the plurality of capacitive sense elements. A method for water-resistant capacitance sensing, the method comprising performing a self-capacitance scan and a mutual capacitance scan, and detecting, by a processing device, a presence of an object with the plurality of sense elements. The method further determines whether the detected presence of the object is legitimate.
Claims18
A capacitive sense apparatus, the apparatus comprising:
- a plurality of capacitive sense elements;
- and
- a capacitance sensor circuit coupled to the plurality of capacitive sense elements, the capacitance sensor circuit configured to perform a self-capacitive scan to measure a self-capacitance on the plurality of capacitive sense elements,
- wherein the self-capacitive scan uses a first baseline to detect a possible touch;
- wherein the capacitance sensor circuit is configured to perform a first mutual capacitive scan to measure a mutual capacitance on the plurality of capacitive sense elements when the possible touch is detected by the self-capacitive scan,
- wherein the mutual capacitive scan uses a second baseline to detect the possible touch;
- wherein the capacitance sensor circuit is configured to validate the possible touch detected by the self-capacitive scan as a legitimate touch when the possible touch is detected by the self-capacitive scan and first mutual capacitive scan;
- wherein the possible touch is not legitimate when the possible touch is detected in only one of the self-capacitive scan and the first mutual capacitive scan;
- wherein the capacitance sensor circuit is configured to perform one or more subsequent self-capacitive scans when the possible touch is not detected by the self-capacitive scan;
- wherein the capacitance sensor circuit is configured to perform a second mutual capacitive scan after a specified period when no touch is detected by the self-capacitive scan and by the one or more subsequent self-capacitive scans within the specified period;
- and
- wherein the capacitance sensor circuit is configured to update the first baseline and the second baseline after the specified period when no touch is detected by the self-capacitive scan and by the one or more subsequent self-capacitive scans within the specified period.
9 more elements
A method for capacitance sensing, the method comprising:
- performing, by a processing device, a self-capacitive scan, wherein the self-capacitive scan measures a self-capacitance of a plurality of sense elements;
- detecting, by the processing device, a possible touch in proximity to the plurality of sense elements based on a first comparison of the self-capacitance measured in the self-capacitive scan and a first baseline;
- performing, by the processing device, a first mutual capacitive scan when the possible touch is detected by the self-capacitive scan, wherein the first mutual capacitive scan measures a mutual capacitance of the plurality of sense elements;
- detecting, by the processing device, the possible touch in proximity to the plurality of sense elements based on a second comparison of the mutual capacitance measured in the first mutual capacitive scan and a second baseline;
- validating, by the processing device, the possible touch detected by the self-capacitive scan as a legitimate touch when the possible touch is detected by the self-capacitive scan and the first mutual capacitive scan, wherein the possible touch is not legitimate when the possible touch is detected in only one of the self-capacitive scan and the first mutual capacitive scan;
- performing, by the processing device, one or more subsequent self-capacitive scans when the possible touch is not detected by the self-capacitive scan;
- performing, by the processing device, a second mutual capacitive scan after a specified period when no touch is detected by the self-capacitive scan and by the one or more subsequent self-capacitive scans within the specified period;
- and
- updating, by the processing device, the first baseline and the second baseline after the specified period when no touch is detected by the self-capacitive scan and by the one or more additional self-capacitive scans within the specified period.
6 more elements
A method for capacitive sensing, the method comprising:
- performing, by a processing device, a self-capacitive scan, wherein the self-capacitive scan measures a self-capacitance of a plurality of sense elements;
- detecting, during the self-capacitive scan, a presence of an object that comes in proximity with the plurality of sense elements, wherein the presence is detected using a first baseline for the self-capacitive scan;
- performing, by the processing device, a first mutual capacitive scan when the presence of the object is detected by the self-capacitive scan, wherein the first mutual capacitive scan measures a mutual capacitance of the plurality of sense elements;
- bypassing the performing of the first mutual capacitive scan when the presence of the object is not detected by the self-capacitive scan;
- detecting, during the first mutual capacitive scan, the presence of the object, wherein the presence is detected using a second baseline for the mutual capacitive scan;
- performing, by the processing device, one or more subsequent self-capacitive scans when no touch is detected by the self-capacitive scan;
- performing, by the processing device, a second mutual capacitive scan after a specified period when no touch is detected by the self-capacitive scan and by one or more subsequent self-capacitive scans within the specified period;
- and
- updating the first baseline and the second baseline after the specified period when no touch is detected by the self-capacitive scan and by the one or more subsequent self-capacitive scans within the specified period.
6 more elements
Dependencies are inferred from the claim text.