Curving comb pixel electrodes reduce color shift in FFS-LCD
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Solution Overview
Problem
Fringe field switching (FFS) mode liquid crystal display devices suffer from color shift issues due to abnormal liquid crystal molecule orientation at elbow portions of comb electrodes, leading to impaired display quality when viewed from oblique angles.
Innovation Solution
The FFS-LCD device incorporates pixel electrodes with curving comb portions that establish a horizontal in-plane electric field in different directions, allowing liquid crystal molecules to twist uniformly and reduce color shift by creating a continuous domain between the common and pixel electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If pixel electrodes include elbow portions to create horizontal in-plane electric field in two directions, then color shift is reduced, but liquid crystal molecules at the elbow portion are abnormally oriented and display quality is impaired
Solution Approach 1:
The patent replaces the elbow portion configuration with curving comb portions that have smooth curved surfaces. This curvature design allows the electric field to be distributed more uniformly without creating concentrated distortion zones, thereby maintaining liquid crystal molecule orientation uniformity while still achieving color shift reduction through the horizontal in-plane electric field in multiple directions.
Solution Approach 2:
The patent changes the geometric parameters of the pixel electrode from straight-line elbow portions to curving portions with specific radius of curvature. This parameter modification eliminates the sharp angles that cause electric field distortion, allowing liquid crystal molecules to align properly while still achieving the desired multi-directional electric field effect for color shift reduction.
2Reliability
If common electrode and pixel electrodes are made of opaque metals, then electrode functionality is improved, but aperture ratio and transmittance are reduced
Solution Approach 1:
The patent changes the optical properties of the electrodes by using transparent conductive materials such as ITO (indium tin oxide) or IZO (indium zinc oxide) instead of opaque metals. This material substitution maintains the electrical conductivity and functionality of the electrodes while significantly improving light transmittance and aperture ratio, allowing more light to pass through the display device.
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 configuration minimizes color shift and maintains uniform display quality even when viewed from angles, as the curving comb portions prevent abnormal electric field distortions and ensure consistent liquid crystal alignment.
Implementation Method 1
When a voltage is applied between the pixel and common electrodes, a horizontal in-plane electric field along different directions that is parallel to a surface of the substrates is established between the curving comb portions of the pixel electrodes and common electrodes. The liquid crystal molecules are twisted so as to align according to the electric field.
Data Source
AI summary
A fringe field switching liquid crystal display (FFS-LCD) device (200) includes a first substrate (210) and a second substrate (220) disposed opposite to each other and spaced apart a predetermined distance, a liquid crystal layer (250) interposed between the first and second substrates, a plurality of gate lines (233) and data lines (234) formed on the second substrates, thereby defining a plurality of pixel regions, and a plurality of pixel electrodes (223) and a plate-like common electrode (221) provided in each of the pixel regions. The pixel electrodes have a plurality of curving comb portions so as to generate a continuous variation electric field between the pixel and common electrodes. Liquid crystal molecules in the FFS-LCD device are twisted in different continuous directions so as to reduce the color shift.