Touch Sensor Noise Calibration via Segmented Signal Processing
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Solution Overview
Problem
Existing touch sensors face challenges in enhancing sensitivity due to noise interference from display panels, particularly common mode noise, which affects the accuracy of touch input detection.
Innovation Solution
The touch sensor design includes noise detecting electrodes and a signal receiving part with amplification and analog-to-digital conversion capabilities, allowing for the detection and calibration of noise signals to improve signal-to-noise ratio and sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If noise detecting electrodes and amplification circuits are added to the touch sensor, then the sensitivity and noise reduction capability are improved, but the device complexity increases
Solution Approach 1:
The touch sensor is divided into functional segments: sensor part with first and second electrodes, signal receiving part with separate amplification and ADC circuits, and processor part. Each segment handles specific tasks (signal generation, noise detection, signal conversion, touch detection) independently, allowing complex functionality to be achieved through modular organization rather than a monolithic complex structure
Solution Approach 2:
A signal receiving part is introduced as an intermediary component between the sensor part and processor. This intermediary includes amplification circuits that boost weak sensor signals and ADC circuits that convert analog signals to digital format, mediating the transition from physical touch detection to digital processing while filtering and conditioning signals along the way
2Measurement precision
If gain calibration and noise offsetting operations are performed, then the signal-to-noise ratio is improved, but the processing time and complexity increase
Solution Approach 1:
The processor performs gain calibration and noise offsetting operations in advance during initialization or setup phases before actual touch input detection begins. By completing these time-consuming calibration operations preliminarily, the system establishes optimized detection parameters ahead of time, allowing rapid real-time touch detection without repeated calibration overhead
Solution Approach 2:
The system implements feedback mechanisms where the processor continuously monitors detection signals and adjusts amplification gain and offset values based on detected noise levels and signal characteristics. This closed-loop feedback allows dynamic optimization of signal-to-noise ratio during operation, maintaining high detection accuracy without requiring constant manual recalibration
Data Source
AI summary
In an embodiment, a touch sensor may include a sensor part including a first electrode and a second electrode, a signal receiving part, an amplifier circuit part connected between the second electrode and the signal receiving part, an analog-to-digital converter part configured to output a digital signal corresponding to a voltage difference between input terminals, and a processor configured to detect a touch input from the sensor part in response to the digital signal when operating in a first mode, and to output a gain control signal for calibrating a gain value of the amplifier circuit part in response to the digital signal when operating in a second mode.