Mitigating spatially correlated noise in data from capacitive sensors
First Claim
1. An input device, comprising:
- a plurality of sensor electrodes in a sensing region of the input device, wherein the plurality of sensor electrodes is categorized into respective groups of sensor electrodes where sensor electrodes in each of the groups of sensor electrodes are affected by a common noise source; and
a processing system coupled to the plurality of sensor electrodes, the processing system is configured to;
determine resulting signals for the sensor electrodes in a first group of the groups of sensor electrodes,compare the resulting signals of the first group to a predefined touch threshold to determine whether an input object is proximate to the sensor electrodes in the first group,calculate at least one offset using the resulting signals based on a determination that the input object is not proximate to the sensor electrodes in the first group, andcompensate for an effect of the common noise source by adjusting the resulting signals using the at least one offset.
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Accused Products
Abstract
This disclosure generally provides an input device with a matrix sensor that includes a plurality of sensor electrodes arranged on a common surface or plane. Moreover, the input device includes routing traces that electrically couple the sensor electrodes to analog front ends (AFEs). Because of the spatial relationships between these electrical components, the sensor electrodes can be categorized into groups where each of the sensors in the group is affected by a common noise source. The capacitive measurements for the sensor electrodes in each of the groups are compared to a touch threshold to determine if an input object (e.g., finger or stylus) is proximate to the sensor electrodes. If the capacitive measurements are below the touch threshold, the input device calculates an offset value that compensates for the noise. After the offset is applied, the compensated capacitive measurements are used to generate a capacitive image.
51 Citations
20 Claims
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1. An input device, comprising:
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a plurality of sensor electrodes in a sensing region of the input device, wherein the plurality of sensor electrodes is categorized into respective groups of sensor electrodes where sensor electrodes in each of the groups of sensor electrodes are affected by a common noise source; and a processing system coupled to the plurality of sensor electrodes, the processing system is configured to; determine resulting signals for the sensor electrodes in a first group of the groups of sensor electrodes, compare the resulting signals of the first group to a predefined touch threshold to determine whether an input object is proximate to the sensor electrodes in the first group, calculate at least one offset using the resulting signals based on a determination that the input object is not proximate to the sensor electrodes in the first group, and compensate for an effect of the common noise source by adjusting the resulting signals using the at least one offset. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A processing system for performing capacitive sensing, comprising:
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an interface configured to couple to a plurality of sensor electrodes in a sensing region of an input device, wherein the plurality of sensor electrodes are categorized into a plurality of groups of sensor electrodes where sensor electrodes in each of the plurality of groups of sensor electrodes are affected by a common noise source; and at least one sensor module configured to; determine resulting signals for the sensor electrodes in a first group of the plurality of groups of sensor electrodes, compare the resulting signals to a predefined touch threshold to determine whether an input object is proximate to the sensor electrodes in the first group, calculate at least one offset using the resulting signals based on a determination that the input object is not proximate to the sensor electrodes in the first group, and compensate for an effect of the common noise source by adjusting the resulting signals using the at least one offset. - View Dependent Claims (10, 11, 12, 13)
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14. A method for performing capacitive sensing using a plurality of sensor electrodes in a sensing region of an input device, comprising:
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determining resulting signals for sensor electrodes in a first group of the plurality of sensor electrodes where the sensor electrodes in the first group are affected by a common noise source; comparing the resulting signals of the first group to a predefined touch threshold to determine whether an input object is proximate to the sensor electrodes in the first group; calculating at least one offset using the resulting signals based on a determination that the input object is not proximate to the sensor electrodes in the first group; and compensating for an effect of the common noise source by adjusting the resulting signals using the at least one offset. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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Specification