Common Electrode Voltage Control for Display Panel Greenish Image
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Solution Overview
Problem
In large size TV and 3D products, the coupling capacitance between data lines and common electrodes leads to short charging time and picture distortion, especially at high driving frequencies, resulting in greenish images despite the use of SVC circuits.
Innovation Solution
A voltage control method for electrodes involves inputting a varying voltage signal to common electrodes based on the voltage variation of data lines, with compensating voltage signals of opposite polarity applied during high and low levels of the total waveform to smooth the output voltage signal, thereby counteracting the influence of data line voltage on common electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a steady voltage signal is input to common electrodes, then the common electrodes maintain stable voltage, but coupling capacitance between data lines and common electrodes causes voltage influence and picture distortion at high driving frequencies
Solution Approach 1:
The patent applies preliminary anti-action by detecting voltage variations on data lines before they affect common electrodes through coupling capacitance, and pre-applying compensating voltage signals to counteract the anticipated voltage influence. This proactive compensation prevents picture distortion before it occurs, resolving the contradiction between maintaining stable common electrode voltage and ensuring picture quality at high driving frequencies.
2Productivity
If driving frequency is increased from 60 Hz to 120 Hz or 240 Hz for large size and 3D products, then productivity and functionality are improved, but charging time for pixels becomes short causing voltage influence on common electrodes and greenish pictures
Solution Approach 1:
The patent implements preliminary action by detecting voltage variations on data lines and applying compensating voltage signals to common electrodes before the coupling capacitance effect can cause picture distortion. This advance compensation enables high driving frequencies (120 Hz, 240 Hz) to be used without the greenish picture problem, thus improving productivity while maintaining picture quality reliability.
3Reliability
If SVC circuit is used to address voltage influence on common electrodes, then some compensation is achieved, but picture distortion and greenish issue remain difficult to overcome at high driving frequencies
Solution Approach 1:
The patent applies feedback by detecting the actual voltage variations on data lines and using this information to dynamically adjust the compensating voltage signals applied to common electrodes. This feedback mechanism provides more accurate compensation compared to fixed SVC circuits, achieving better picture quality while maintaining manageable device complexity through intelligent control.
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 effectively prevents picture distortion by ensuring a smooth voltage signal from common electrodes, avoiding the greenish issue caused by data line voltage influence, even at high driving frequencies.
Implementation Method 1
there exists coupling capacitance between data lines 20 and common electrodes 30
Data Source
AI summary
A voltage control method and device for electrodes, wherein the method includes inputting a varying voltage signal to common electrodes on an array substrate. The solution of the present application may avoid the problem of greenish picture of products due to influence of data line voltage on common electrodes.