Capacitive Touch Screen Interference Adaptation
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Solution Overview
Problem
Capacitive touch screens are adversely affected by electrically conductive mediums such as water, leading to reduced sensitivity and detection precision, with existing methods failing to accurately differentiate between single and multi-finger touches when the screen is covered.
Innovation Solution
A touch screen control method and device that identifies the interference level of electrically conductive mediums by comparing actual capacitance values to reference values, allowing the system to switch operation modes to mitigate the impact, such as switching from multi-finger to single-finger mode when the screen is covered, and reporting the current operation mode to the CPU.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If capacitive touch screen uses conventional touch detection methods, then multi-point touch detection can be realized, but detection precision deteriorates when electrically conductive medium covers the screen surface
Solution Approach 1:
The patent dynamically switches between mutual capacitance mode and self-capacitance mode based on the detected interference level. When conductive medium is detected, the system transitions from mutual capacitance scanning to self-capacitance scanning, adapting the detection method to current environmental conditions to maintain detection precision.
Solution Approach 2:
The patent changes the operational parameters of the touch screen by switching between different capacitance detection modes (mutual vs. self-capacitance) and adjusting scanning strategies based on the presence and level of conductive medium interference, thereby optimizing detection accuracy under varying conditions.
2Measurement precision
If the touch screen switches operation modes to mitigate interference, then detection precision improves, but device complexity increases
Solution Approach 1:
The patent implements a feedback mechanism where the touch controller continuously monitors capacitance values to detect the presence and level of conductive medium interference, then uses this feedback information to automatically switch between detection modes and scanning strategies, maintaining precision without requiring complex manual intervention.
Solution Approach 2:
The touch screen system autonomously detects interference conditions and self-adjusts its operation mode without external intervention. The controller automatically determines when to switch between mutual and self-capacitance modes based on real-time capacitance measurements, reducing the need for complex external control logic.
3Measurement precision
If the system uses self-capacitance scanning to detect single-point touch, then detection precision improves under water coverage, but the ability to detect multi-point touch deteriorates
Solution Approach 1:
The patent dynamically selects between self-capacitance and mutual capacitance scanning modes based on the detected interference level and touch pattern. When water coverage is detected, self-capacitance mode is used for precise single-point detection; when no water is present or interference is low, mutual capacitance mode enables multi-point touch detection, thus adapting to different operational conditions.
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 significantly improves the sensitivity and detection precision of capacitive touch screens by adapting operation modes based on the interference level of conductive liquids, ensuring accurate touch detection even under conditions of partial or full coverage.
Implementation Method 1
A capacitive touch screen includes transversal and longitudinal electrode arrays made from ITO (Indium Tin Oxide). The transversal and longitudinal electrode arrays constitute a plurality of test points equally distributed on the screen surface. As self-capacitance can be produced between adjacent electrodes, single-point touch detection can be realized by collecting the change of self-capacitance values of test points by way of self-capacitance scanning. In addition, as mutual capacitance can be produced between adjacent electrodes, multi-point touch detection can be realized by collecting the change of mutual capacitance values of test points by way of mutual capacitance scanning.
Data Source
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AI summary
A touch screen control method and device thereof are provided. The method includes: acquiring (102) the actual capacitance values of test points on the touch screen; identifying (104) the interference level of the electrically conductive medium according to change of the actual capacitance values relative to reference capacitance values; and controlling (106) the touch screen under the operation mode corresponding to the interference level. The present invention solves the problem that the sensitivity and detection precision of the capacitive touch screen are seriously impacted when the capacitive touch screen surface is covered with electrically conductive mediums, to a large extent mitigating the effect of electrically conductive mediums on the touch screen, and improving the sensitivity and detection precision of the touch screen by controlling the touch screen under the operation mode corresponding to the interference level according to the interference level of the electrically conductive mediums.