Touch Screen Calibration Method Correcting Coordinate Mismatch
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Solution Overview
Problem
The inconsistency between the coordinate systems of the display module and the sensor module in touch screens, caused by manufacturing limitations, leads to calibration errors and inaccuracies in determining touch points, affecting the touch screen's functionality and user input accuracy.
Innovation Solution
A calibration method that involves receiving coordinate values from both modules, calculating initial calibration formulas based on multiple correspondences, adjusting sensing points, and generating a second set of formulas to accurately transform coordinates between the two systems, thereby correcting for rotation, scaling, and shift errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If coordinate systems of display module and sensor module are made completely consistent during manufacture, then touch point accuracy is improved, but manufacturing complexity and cost increase due to requiring precise alignment tools and skills
Solution Approach 1:
The patent applies preliminary action by performing coordinate system calibration during the assembly process rather than requiring perfect pre-alignment. The calibration module captures images of calibration patterns before final assembly, allowing coordinate systems to be matched through image processing and transformation calculations, thus reducing manufacturing complexity while maintaining accuracy.
Solution Approach 2:
The patent introduces an intermediary calibration module that acts as a mediator between the display module and sensor module. This calibration module contains known calibration patterns that enable the system to establish coordinate transformations without requiring direct precise alignment between the display and sensor coordinate systems, thereby simplifying manufacturing while ensuring touch accuracy.
2Ease of manufacture
If calibration is performed using traditional methods with fixed coordinate assumptions, then manufacturing process is simplified, but calibration accuracy deteriorates due to ignoring rotation, scaling, and shift errors
Solution Approach 1:
The patent applies dynamics by making the coordinate transformation parameters adjustable and optimizable rather than fixed. The system calculates initial transformation parameters and then iteratively adjusts them based on captured calibration images, allowing the coordinate systems to be dynamically aligned despite manufacturing variations, thus improving accuracy without significantly complicating the manufacturing process.
Solution Approach 2:
The patent implements feedback by using captured calibration pattern images to evaluate and refine the coordinate transformation parameters. The system compares detected calibration pattern positions with expected positions, calculates errors, and adjusts transformation parameters accordingly, creating a closed-loop calibration process that improves accuracy while maintaining ease of manufacture.
Data Source
AI summary
The present invention provides a calibration method of a touch screen which comprises a display module and a sensor module. The calibration method comprises the following steps: receiving coordinate values of multiple display points shown on the display module; receiving coordinate values of multiple sensing points received by the sensor module, wherein the multiple sensing points are corresponding to the multiple display points, respectively, for forming at least four multiple correspondences; calculating a first set of calibration formulas according to the multiple correspondences; adjusting the multiple sensing points according to the first set of calibration formulas; and calculating a second set of calibration formulas according to the adjusted sensing points.