Pixel Structure Charge Releasing Device Image Sticking
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Solution Overview
Problem
Conventional MVA TFT-LCD panels suffer from image sticking due to charge imbalance and trapping in the alignment film, leading to color washout and poor display quality when viewed from different angles.
Innovation Solution
Incorporating a charge releasing device, such as a capacitor or a thin film transistor, electrically connected to the pixel electrodes and scan lines, to prevent charge accumulation and maintain balanced voltage levels, thereby reducing image sticking and enhancing display stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a floating pixel electrode is used to compensate color saturation, then color washout phenomenon is avoided, but charge accumulation occurs in the alignment film causing image sticking
Solution Approach 1:
A charge releasing device (capacitor or transistor) is introduced as an intermediary component between the floating pixel electrode and the alignment film. This device mediates the charge accumulation problem by providing a controlled discharge path, allowing the floating electrode to maintain color saturation compensation while preventing charge buildup that causes image sticking.
Solution Approach 2:
The electrical parameters (voltage level, charge distribution) of the floating pixel electrode are dynamically controlled through the charge releasing device. By adjusting the discharge timing and amount, the system maintains the voltage differential needed for color saturation while preventing excessive charge accumulation in the alignment film.
2Illumination intensity
If multiple pixel electrodes with different voltage levels are used, then color washout is prevented, but device complexity increases
Solution Approach 1:
The floating pixel electrode structure serves multiple functions automatically: it provides color saturation compensation through its inherent capacitance coupling while the charge releasing device automatically manages charge distribution. This self-regulating system reduces the need for additional complex control circuitry.
3Reliability
If charges are trapped in the alignment film, then voltage level shifts occur, but display stability is compromised
Solution Approach 1:
The charge releasing device creates a feedback mechanism that monitors and corrects charge distribution in the alignment film. When charge accumulation begins to cause voltage shifts, the device activates to release excess charges, maintaining stable voltage levels and preventing display instability.
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
The charge releasing device effectively reduces charge accumulation and maintains balanced voltage levels, preventing image sticking and ensuring consistent display quality across various viewing angles without affecting the aperture ratio or requiring significant process modifications.
Implementation Method 1
the floating pixel electrode 214 keeps a voltage level Vcc by capacitor coupling effect (C.C.)
Implementation Method 2
When the MVA TFT-LCD panel 200 is driven to display images, the pixel electrode 212 is coupled to a voltage level Vdata, and the floating pixel electrode 214 keeps a voltage level Vcc by capacitor coupling effect (C.C.)
Data Source
AI summary
A pixel structure electrically connected to a scan line and a data line, includes an active device, a first pixel electrode, a second pixel electrode, a capacitor coupling electrode and a charge releasing device. The active device is electrically connected to the scan line and the data line. The second pixel electrode is electrically isolated from the first pixel electrode. The capacitor coupling electrode is disposed under the second pixel electrode and electrically connected to the data line through the active device. The charge releasing device is electrically connected to the second pixel electrode. The above-described pixel structure is able to effectively solve the image sticking problem. In addition, further provides an active matrix substrate which is able to avoid the image sticking effect.