Touch Panel Coordinate Correction Using Polynomial Curve Approximation
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Solution Overview
Problem
Existing touch panel devices face inaccuracies in detecting input coordinates due to curvilinear distortion of equipotential lines caused by electrode resistance values, leading to deviations that cannot be accurately corrected with first-order polynomial equations and result in overcurrent issues or increased costs with high-pressure resistance components.
Innovation Solution
A touch panel device with a detection unit and a correction unit that approximates curves using second-order or higher-order polynomial equations to correct detected coordinates, specifying regions and calculating distances to define accurate coordinates without requiring massive hardware or complex multiple-stage processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If electrodes with low resistance values are used to reduce coordinate deviation, then measurement precision is improved, but overcurrent flows through electronic components which may break them
Solution Approach 1:
The patent changes the mathematical model parameters from first-order to second-order or higher-order polynomial equations to accurately compensate for coordinate deviations without requiring low-resistance electrodes, thus avoiding overcurrent issues while maintaining detection precision
Solution Approach 2:
The patent introduces curve approximation equations as an intermediary mathematical model between the detected coordinates and the actual pressed point coordinates, enabling accurate coordinate correction without modifying the physical electrode resistance
2Measurement precision
If electrodes with low resistance values are used to reduce coordinate deviation, then measurement precision is improved, but device complexity increases due to need for high-pressure resistance components
Solution Approach 1:
The patent changes the correction algorithm from simple first-order polynomials to second-order or higher-order polynomial equations, achieving accurate coordinate correction through mathematical complexity rather than hardware complexity, thus avoiding the need for high-pressure resistance components
3Speed
If first-order polynomial equations are used for coordinate correction, then processing speed is improved, but measurement precision is insufficient to accurately correct curvilinear distortion
Solution Approach 1:
The patent applies second-order or higher-order polynomial equations that can represent curved surfaces, enabling accurate modeling and correction of curvilinear distortion in the resistance film that first-order linear equations cannot capture
Solution Approach 2:
The patent increases the polynomial order from first-order to second-order or higher, adding curvature terms to the mathematical model that accurately represent the curvilinear distortion while maintaining computational efficiency
Data Source
AI summary
A touch panel device includes: a detection unit that detects coordinates of a pressed point on an input surface of a touch panel; and a correction unit that corrects the coordinates detected by the detection unit to obtain corrected coordinates, wherein the correction unit approximates, when a predetermined number of reference points arranged on the input surface are pressed, curves passing through coordinates of the reference points by second order or higher order polynomial equations, specifies, when an arbitrary point on the input surface is pressed, a region including coordinates of the arbitrary point from regions obtained by dividing the input surface by the curves, calculates distances from the coordinates of the arbitrary point to curves that define the specified region among the curves with the second order or higher order polynomial equations, and calculates the corrected coordinates based on a location of the specified region and the distances.