LCD Shield Member for Floating Electrode Image Sticking
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Solution Overview
Problem
Conventional liquid crystal display devices with floating sub picture element electrodes suffer from image sticking due to direct-current voltage components and variations in liquid crystal capacitance, leading to display quality issues like wash out and image sticking ratios exceeding 10%.
Innovation Solution
The implementation of a liquid crystal display device with a shield member to electrically shield the sub picture element electrode capacitively coupled to the control electrode, and the use of a high-resistance resistor between the floating sub picture element electrode and the control electrode, along with forming a second auxiliary capacitance parallel to the liquid crystal capacitance to reduce image sticking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a floating sub picture element electrode is used to suppress wash out, then display quality is improved, but image sticking occurs due to direct-current voltage components
Solution Approach 1:
A shield member is introduced as an intermediary component between the floating sub picture element electrode and the bus lines (gate bus line and data bus line). This shield member, connected to a fixed potential, blocks the direct-current voltage components from reaching the floating electrode, thereby preventing image sticking while preserving the wash out suppression functionality.
Solution Approach 2:
The harmful direct-current voltage components are extracted and isolated from the floating sub picture element electrode by introducing the shield member. The shield member acts as a barrier that separates the AC signal path from the DC voltage components, allowing the floating electrode to maintain its wash out suppression capability without suffering from image sticking.
2Illumination intensity
If capacitive coupling is applied to sub picture element electrodes, then wash out is suppressed, but liquid crystal capacitance variations cause image sticking
Solution Approach 1:
The shield member serves as a mediator that isolates the floating sub picture element electrode from the bus lines, preventing variations in liquid crystal capacitance from causing image sticking. By blocking the path for capacitance variations, the shield member allows the capacitive coupling to maintain its wash out suppression effect without the reliability issues.
3Ease of operation
If direct-current voltage components are applied to bus lines, then display operation is enabled, but image sticking occurs at high ratios
Solution Approach 1:
The shield member is positioned between the bus lines and the floating sub picture element electrode, acting as a mediator that allows display operation to continue while blocking the harmful direct-current voltage components. This intermediary structure enables the display to function with bus line voltage components without suffering from high image sticking ratios.
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 image sticking by canceling out direct-current voltage components and reducing the influence of liquid crystal capacitance variations, maintaining a favorable display quality with image sticking ratios below 5%.
Implementation Method 1
a shield member for electrically shielding connection between the sub picture element electrode capacitively coupled to the control electrode and at least any of the gate bus line and the data bus line
Implementation Method 2
a capacitor connected between the sub picture element electrode and the common electrode
Data Source
AI summary
A sub picture element electrode directly connected to a thin film transistor is disposed between a floating sub picture element electrode capacitively coupled to a control electrode and a gate bus line in order to prevent injection of electric charges from the gate bus line to the floating sub picture element electrode. Moreover, a shield pattern electrically connected to an auxiliary capacitance bus line is formed between the floating sub picture element electrode and a data bus line. This shield pattern avoids injection of electric charges from the data bus line to the floating sub picture element electrode.