Capacitive Touch Noise Immunity via Hybrid Self-Mutual Sensing

The patent combines self-capacitance sensing and mutual-capacitance sensing into a hybrid sensing system. The self-capacitance channel provides high sensitivity for detecting light touches, while the mutual-capacitance channel provides noise immunity for accurate touch point identification. By merging these two sensing modalities and fusing their outputs, the system achieves both high sensitivity and high reliability without compromising either parameter.

The patent dynamically adjusts the sensing threshold based on the sensed values from both self-capacitance and mutual-capacitance channels. Instead of using a fixed high threshold that compromises hardware support, the system adapts the threshold parameter in real-time based on the combined input from both sensing modalities, maintaining noise immunity while preserving hardware compatibility and responsiveness.

The patent implements a feedback mechanism where the sensing system continuously monitors the quality of sensed values from both self-capacitance and mutual-capacitance channels. When noise is detected, the system uses the complementary information from the other channel to correct or validate the sensed values in real-time, rather than discarding the entire frame and re-sensing. This feedback-based correction maintains high frame rates while ensuring accurate touch point identification.

The patent uses the self-capacitance channel as an intermediary to enhance the reliability of mutual-capacitance-based touch point identification. The self-capacitance sensed values, which have high signal-to-noise ratio, serve as a reference or mediator to validate and correct the mutual-capacitance measurements. This intermediary role allows the system to leverage the strengths of both sensing modalities, achieving both high signal-to-noise ratio and accurate touch point identification.