Arc-Shaped Pixel Electrodes for LCD Viewing Angle and Color Shift
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Solution Overview
Problem
Liquid crystal display (LCD) devices with vertical alignment (VA) suffer from color shift and compromised display quality when viewed from large angles due to differences in grayscale voltages between sub-pixels, leading to non-uniform viewing experiences.
Innovation Solution
The implementation of a pixel unit design featuring thin film transistors (TFTs) with arc-shaped electrode units arranged concentrically around the periphery, along with different VA TFT designs in primary and secondary pixel regions, allowing for distinct voltage levels and improved liquid crystal molecule alignment, thereby reducing color shift and enhancing viewing angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If pixels are divided into two sub-pixels with different grayscale voltages to achieve uniform viewing quality, then viewing angle performance is improved, but color shift occurs due to different transmittance
Solution Approach 1:
The pixel electrode is divided into multiple arc-shaped electrode units arranged at intervals along the axial direction around the TFT periphery. These electrode units are electrically connected together to form a unified electrode structure that distributes voltage more uniformly across the liquid crystal layer, eliminating the need for separate sub-pixels with different grayscale voltages.
Solution Approach 2:
The patent employs arc-shaped electrode units with curved geometry arranged concentrically around the TFT. This curved configuration creates a more uniform electric field distribution in the radial direction, improving liquid crystal alignment consistency across different viewing angles without causing color shift.
2Ease of manufacture
If multiple arc-shaped electrode units are arranged around the TFT periphery to achieve isotropic liquid crystal alignment, then color shift is minimized, but device complexity increases
Solution Approach 1:
Multiple arc-shaped electrode units are electrically connected together to function as a single unified pixel electrode. This merging approach maintains the benefits of distributed voltage application for isotropic liquid crystal alignment while simplifying the control structure, as all electrode units respond to the same voltage signal from the source electrode.
Solution Approach 2:
The arc-shaped electrode units serve multiple functions simultaneously: they distribute voltage uniformly around the TFT periphery, create isotropic liquid crystal alignment, improve viewing angle performance, and eliminate color shift. This multi-functionality reduces the need for additional separate components or structures.
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 solution effectively minimizes color shift and enhances viewing angles by achieving isotropic liquid crystal molecule alignment and utilizing differences in width-to-length ratio and capacitance between primary and secondary pixel electrodes, resulting in improved display quality across various viewing angles.
Implementation Method 1
LCD produces electrical field by applying voltages to pixel electrodes and common electrodes on the substrates. The electrical field controls the deflection of liquid crystal molecules in the liquid crystal layer.
Implementation Method 2
The electrical field controls the deflection of liquid crystal molecules in the liquid crystal layer.
Data Source
AI summary
The present invention teaches a pixel unit including thin film transistors (TFTs) and pixel electrodes corresponding to the TFTs. The pixel electrodes are connected to the source electrodes of the TFTs. Each pixel electrode includes multiple arc-shaped electrode units arranged at intervals along an axial direction around a periphery of a corresponding TFT. The electrode units are electrically connected together. The present invention adopts arc-shaped pixels (similar to concentric circles) so that liquid crystal molecules are closer to being isotropic. Then, by having different vertical alignment (VA) TFT designs in the primary pixel region and secondary pixel region and utilizing the differences in W/L and capacitance, different voltage levels for primary pixel electrode and secondary pixel electrode are achieved. The color shift problem is improved and the viewing angle is enhanced.