Capacitive Touch Noise Removal via Channel Segmentation
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Solution Overview
Problem
Capacitive touch screens face challenges in accurately detecting touch information due to common noise affecting all channels, particularly in environments without shielding, leading to difficulties in distinguishing touch signals from noise.
Innovation Solution
A method involving acquiring base lines, calculating touch strengths, determining a difference representative value, and removing the influence of common noise using this value to enhance the accuracy of touch information detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If shielding is not used to reduce device complexity and cost, then common noise affects all channels making touch detection inaccurate
Solution Approach 1:
The patent segments the touch sensing channels into multiple independent measurement paths, allowing individual processing of each channel's signal. By calculating touch strengths separately for each channel and then comparing them, the system can identify and remove common noise that affects all channels equally, achieving accurate touch detection without physical shielding.
Solution Approach 2:
The patent introduces an intermediary processing step that calculates a representative value (average or median) of touch strengths from multiple channels. This intermediary value serves as a reference to identify and remove common noise components, enabling accurate touch detection in unshielded environments by mediating between the noisy raw signals and the final touch determination.
2Device complexity
If common noise removal processing is not performed, then the processing complexity is low, but touch information detection accuracy deteriorates
Solution Approach 1:
The patent performs preliminary calculation of touch strengths for each channel before making the final touch detection decision. By pre-processing the signals to extract touch strength values and comparing them across channels, the system removes common noise early in the processing pipeline, simplifying subsequent detection logic while maintaining high accuracy.
Solution Approach 2:
The patent implements a feedback mechanism where the calculated touch strengths from multiple channels are compared and used to adjust the final touch detection result. The system uses the representative value of touch strengths as feedback to identify common noise patterns and remove them, creating a closed-loop processing system that continuously optimizes detection accuracy.
Data Source
AI summary
Provided are a method of removing common noise and a method of detecting touch information. The method of removing common noise includes acquiring base lines, acquiring raw data, calculating touch strengths (TSs) using the base lines and the raw data, calculating a difference representative value between the TSs and a reference level, and removing influence of common noise from the TSs using the difference representative value.