Touch Screen Signal Measurement Phase Delay Compensation
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Solution Overview
Problem
Capacitive touch screens face challenges in accurately detecting touches due to noise interference from the human body and phase differences in signal delays through RC circuits, leading to poor signal-to-noise ratios and incorrect location determination.
Innovation Solution
A signal measuring method and device that compensates for phase delays by providing different delay times to driving electrodes, optimizing signals for the touch screen by determining and applying specific delay phase differences to each driving electrode, ensuring accurate signal measurement and noise reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If signals are measured without phase delay compensation, then the measurement process is simple, but the signal-to-noise ratio is poor and touch location accuracy deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing optimal phase delay values for each driving electrode in a lookup table before actual touch detection. During operation, the system simply retrieves the appropriate delay value from the table and applies it, avoiding complex real-time calculations while maintaining high measurement precision
Solution Approach 2:
The patent changes the phase delay parameter for each driving electrode based on its specific electrical characteristics. By adjusting the phase delay parameter individually for each electrode, the system optimizes signal-to-noise ratio and improves touch location detection accuracy without requiring complex hardware modifications
2Reliability
If different phase delays are applied to different driving electrodes, then signal optimization improves, but the control system complexity increases
Solution Approach 1:
The system performs preliminary characterization of each driving electrode's electrical properties and stores the optimal phase delay values in advance. This pre-computation approach ensures reliable signal measurement while keeping the control circuit simple, as it only needs to retrieve and apply stored values rather than perform complex real-time adjustments
Solution Approach 2:
The system automatically determines and applies the appropriate phase delay for each electrode based on pre-stored characteristics, without requiring manual calibration or complex external control. This self-service approach improves measurement reliability while minimizing control circuit complexity
3Measurement precision
If phase delay compensation is implemented, then signal-to-noise ratio improves, but the processing time increases
Solution Approach 1:
The optimal phase delay values are calculated and stored in a lookup table during system initialization or calibration phase. During actual touch detection, the system simply retrieves the pre-determined delay value from the table and applies it immediately, achieving high signal-to-noise ratio without adding significant processing time to the detection cycle
Solution Approach 2:
The phase delay compensation is applied periodically at fixed intervals during the touch detection process, synchronized with the driving signal frequency. This periodic application ensures optimal signal-to-noise ratio while maintaining efficient processing timing
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances the accuracy of touch location detection by optimizing signal levels and reducing noise interference, resulting in improved signal-to-noise ratios and precise touch detection.
Implementation Method 1
the driving electrodes being provided with the driving signal being mutual capacitively coupled with the sensing electrodes
Data Source
AI summary
Each one or each set of driving electrodes of a touch screen corresponds to a delay phase difference. Whenever a driving signal is provided to one or a set of the driving electrodes, a signal on at least one of sensing electrodes of the touch screen is measured after being delayed by the delay phase difference corresponding to the one or the set of the driving electrodes being provided with the driving signal.