In-Cell Touch Panel Position Detection Using Vector Angle Minimization
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Solution Overview
Problem
Existing touch position detection methods in flat panel displays are inefficient due to high computational complexity and inaccuracies caused by external illuminance and shadow deviations, particularly when the user's finger approaches from non-standard directions or overlaps edge sensor areas.
Innovation Solution
A method and device that generate touch data from a touch sensor array, perform binary and filtering operations to correct difference data, determine effective areas, calculate central coordinates, and compute reference and position vectors to accurately detect touch coordinates by minimizing the angle between these vectors, thereby overcoming computational inefficiencies and directional inaccuracies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If matrix operations (determination matrix, eigenvector matrix, eigenvalue matrix) are performed to detect touch coordinates, then measurement precision is improved, but device complexity and operation time increase to infinity
Solution Approach 1:
The patent extracts only the essential computational elements needed for touch coordinate detection from the complex matrix operation framework. Instead of performing full determination matrix, eigenvector matrix, and eigenvalue matrix operations, the invention extracts and applies only the critical calculations necessary to identify the quadratic curve representing the fingertip, thereby dramatically reducing computational complexity while preserving detection accuracy
Solution Approach 2:
The patent applies partial action by performing only the necessary subset of matrix operations required for touch detection. Rather than executing complete matrix algorithms that would lead to infinite operation time, the invention performs partial calculations focused specifically on identifying the quadratic curve of the fingertip region, achieving sufficient precision without the burden of exhaustive computational procedures
2Productivity
If upward priority manner is used to detect touch coordinate, then productivity is improved, but measurement precision deteriorates when finger approaches from non-bottom directions
Solution Approach 1:
The patent inverts the conventional upward priority scanning approach by adopting a downward priority scanning manner. Instead of scanning from the top of the difference data downward and selecting the first sensed point, the invention scans from the bottom upward and selects the last sensed effective point within the quadratic curve region. This inversion correctly identifies the fingertip position regardless of whether the finger approaches from the bottom, top, left, or right, thereby maintaining both high detection speed and accurate coordinate measurement
3Adaptability or versatility
If edge light amount decision manner is used to determine scanning direction, then adaptability is improved, but measurement precision deteriorates due to initialization difficulty and panel deviations
Solution Approach 1:
The patent creates a simplified computational model (quadratic curve representation) that copies only the essential characteristics of the fingertip shadow region. By representing the complex shadow pattern as a quadratic curve and using polynomial fitting, the invention captures the fundamental geometric properties needed for accurate touch detection without being affected by panel-specific deviations or initialization issues that plague the edge light amount decision method
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 enables rapid and accurate detection of touch coordinates, improving performance across various approaching directions and reducing errors caused by external factors, ensuring precise fingertip detection on flat panel displays.
Implementation Method 1
a sensor thin film transistor (TFT) differently generating a light current 'i' depending on a touch or non-touch operation
Data Source
AI summary
A method and a device for detecting a touch position and a flat panel display using the method and the device are disclosed. The touch position detecting method includes generating touch data from a touch sensor array; computing the touch data input in each of adjacent frames to generate difference data and then performing at least one binary operation and a filtering operation on the difference data to correct the difference data; determining an effective area and then calculating a first central coordinate and a second central coordinate; computing a reference vector between the first central coordinate and the second central coordinate, a position vector between a position coordinate and the second central coordinate, and an angle between the reference vector and the position vector; and determining the position coordinate on the touch boundary portion at the angle having a minimum value as a touch coordinate.