Synaptics Incorporated
Dynamic differential algorithm for side touch signals

Abstract:

Input devices described herein include sensing regions that permit the device to identify a location of input objects along a side of the device. To perform gesture detection, an input device selects baseline signals which are subtracted from capacitive sensing signals captured using the sensor electrodes in the sensing region. Doing so results in delta signals that represent the difference between the capacitive sensing signals and the baseline signals. In one embodiment, the baseline signals are selected from capacitive sensing signals received during previous capacitive frames. In one example, the input device uses the capacitive sensing signals received during the Nth previous capacitive frame as the baseline signals. Alternatively, the input device may determine which frame has capacitive sensing signals that vary the most from the current sensing signals and use that frame as the baseline.