Touch Panel Differential Detection Method for Ghost Point Elimination
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Solution Overview
Problem
Conventional capacitive touch panels can only detect single-point touches and face challenges in accurately identifying the coordinates of multiple touch points due to ghost points and signal masking issues.
Innovation Solution
A differential detection method for touch panels that employs a plurality of scan electrodes and sensing electrodes along orthogonal directions, using feature difference values to calculate and adjust the feature values of sensing points, allowing for precise detection of single or multiple touch points without ghost-point problems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional capacitive touch panel detection method is used, then single-point touch detection is achieved, but multiple touch point detection accuracy deteriorates due to ghost points and signal masking
Solution Approach 1:
The touch panel detection is divided into multiple scanning operations, where scan electrodes sequentially select different sensing electrodes to perform multiple measurements. This segmentation allows the system to collect data from different perspectives and reconstruct accurate touch point coordinates even when multiple touches occur, eliminating ghost points and signal masking issues.
Solution Approach 2:
The system uses feature difference values from multiple sensing electrodes as feedback to calculate and adjust touch point coordinates. By comparing measurement results from different scan electrode combinations and using differential calculations, the system iteratively refines the detected coordinates to eliminate errors caused by multiple simultaneous touches.
2Measurement precision
If feature difference values from multiple sensing electrodes are used, then multiple touch point detection accuracy is improved, but calculation complexity increases
Solution Approach 1:
The complex calculation process is segmented into distinct steps: first calculating feature difference values between adjacent sensing electrodes, then using these differences to determine coordinate offsets, and finally applying corrections iteratively. This segmentation makes the algorithm more manageable and implementable despite the inherent complexity of multi-point detection.
Solution Approach 2:
The system performs more measurements than strictly necessary by using multiple scan electrodes and sensing electrode combinations. This excessive action generates redundant data that, while increasing calculation workload, provides multiple pathways to verify and correct touch point coordinates, ultimately improving accuracy without requiring equally complex correction algorithms.
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
Enables accurate and precise detection of coordinate information for single or multiple touch points, improving the accuracy and reliability of touch panel operations.
Implementation Method 1
the capacitive touch panel with applied certain electric signals are used. When a finger touches any point on the capacitive touch panel, the finger would take away the charges coupled onto the capacitive touch panel so that the currents of the four-corner connection electrodes are changed. By detecting the energy variation and the difference thereof on the above-mentioned four-corner connection electrodes
Data Source
AI summary
A touch panel and a differential detection method thereof are disclosed. A controller provides a driving signal to the i-th scan electrode. During providing the driving signal to the i-th scan electrode, the controller senses the feature difference value between two neighboring sensing electrodes within the plural sensing electrodes, and senses the feature difference value ΔCi between the k-th sensing electrode within the sensing electrodes and a reference feature value, in which the feature difference values between the j-th sensing electrode and the (j+1)-th sensing electrode is represented by ΔC(i,j). The controller set the feature value of a base sensing point within a plurality of sensing points of the touch panel as a base feature value, and use the base feature value, the feature difference values ΔCi and the feature difference values ΔC(i,j) to calculate the feature values of the sensing points.