Resistive Touch Panel Multi-Point Detection via Sequence Scanning
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Solution Overview
Problem
Conventional resistive touch panels cannot accurately detect multiple touch points due to circuit design limitations, leading to misjudgment of touch point positions.
Innovation Solution
A touch panel with a resistive pressure-sensing matrix and sequence scan driver, featuring M X-axis sensing circuits and N Y-axis sensing lines, where the ith X-axis sensing line and jth Y-axis sensing line are short-circuited when pressed, and a scanning voltage is applied in each scanning period to determine touch coordinates using comparators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional resistive touch panel circuit design is used, then the device complexity is low, but the measurement precision of multiple touch points deteriorates
Solution Approach 1:
The sensing period is divided into N scanning periods, with each scanning period dedicated to detecting one Y-axis sensing line. This temporal segmentation allows the system to sequentially scan through all Y-axis lines and detect multiple touch points without requiring complex simultaneous multi-point detection circuits.
Solution Approach 2:
The sequence scan driver applies scanning voltages to Y-axis sensing lines in a periodic manner, cycling through each line in successive scanning periods. This periodic scanning approach enables accurate detection of multiple touch points by capturing voltage changes on X-axis sensing lines during each specific scanning period.
2Measurement precision
If sensor spacers with voltages are applied to detect touch points, then the measurement precision improves, but the device complexity increases due to additional sensing circuits
Solution Approach 1:
The patent combines the sensing functions into a unified resistive pressure-sensing matrix where X-axis sensing lines and Y-axis sensing lines interact through pressure-induced short circuits. This merging eliminates the need for separate sensor spacers with embedded voltages, reducing device complexity while maintaining detection accuracy.
Solution Approach 2:
The scanning voltage applied to Y-axis sensing lines serves multiple functions: it activates the sensing mechanism, provides the reference for voltage comparison, and enables sequential scanning across all Y-axis lines. This multi-functionality reduces the need for additional dedicated sensing circuits.
3Productivity
If multiple regions are simultaneously pressed, then the productivity of touch detection increases, but the measurement precision deteriorates due to misjudgment of touch point positions
Solution Approach 1:
By dividing the detection process into N sequential scanning periods, each dedicated to one Y-axis line, the system can accurately identify which specific X-axis and Y-axis lines are activated. This temporal segmentation prevents misjudgment even when multiple regions are pressed simultaneously, as each touch point is detected in its designated scanning period.
Solution Approach 2:
The sequence scan driver uses feedback from voltage comparisons during each scanning period to determine touch point positions. By comparing voltages on X-axis sensing lines against reference voltages during each scanning period, the system can accurately identify multiple touch points without cross-interference, maintaining precision under multi-point contact 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
Enables accurate detection of multiple touch points without misjudgment, reducing the need for additional sensing circuits and saving costs, while maintaining precision in determining the positions of each touch point.
Implementation Method 1
the ith X-axis sensing line and the jth Y-axis sensing line are short-circuited when a preset range covering an overlapped region between the ith X-axis sensing line and the jth Y-axis sensing line of the resistive pressure-sensing matrix is pressed
Data Source
AI summary
The present invention relates to a method for detecting touch points and a touch panel using the same. The method includes the steps of: providing a resistive pressure-sensing matrix includes M X-axis sensing lines and N Y-axis sensing lines, wherein the ith X-axis sensing line and the jth Y-axis sensing line are short-circuited when a preset range covering an overlapped region between the ith X-axis sensing line and the jth Y-axis sensing line is pressed; applying a scanning voltage to the pth Y-axis sensing line in a pth scanning period; detecting the M X-axis sensing lines to judge whether the scanning voltage is detected; and determining a touch coordinate as (q, p) when the qth X-axis sensing line receives the scanning voltage in the pth scanning period, wherein M, N, i, p and q are positive integers, 0<i, q<=M and 0<p<=N.