Vertical Alignment LCD Electrode Triangle Cuts Anti-Viewing Nonuniformity

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Solution Overview

Problem

Conventional vertical alignment liquid crystal display devices suffer from display nonuniformity when viewed from the anti-viewing angle due to oblique electric fields generated between electrodes, leading to uneven liquid crystal molecule orientation and resulting in grainy or degraded image quality.

Innovation Solution

The solution involves forming specific electrode patterns with triangle cuts or apertures on the common electrodes, where the liquid crystal directors defined by the alignment process at the center of the pixel and those defined by the oblique electric field near the edges are opposite, ensuring uniform distribution of liquid crystal directors and minimizing the formation of black crosses, which are regions where light cannot pass through.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If conventional electrode patterns are used in vertical alignment liquid crystal display devices, then the device structure is simple, but display nonuniformity occurs when viewed from the anti-viewing angle due to oblique electric fields

Engineering Contradiction:
Improveelectrode pattern structureVSAvoiddisplay uniformity
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent applies asymmetry by forming triangle cuts or apertures in the electrode patterns. These asymmetric structures modify the electric field distribution to counteract the oblique electric fields that cause display nonuniformity from anti-viewing angles, thereby achieving display uniformity without significantly increasing device complexity

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent implements local quality by positioning triangle cuts or apertures at specific locations on the electrode patterns where oblique electric fields are generated. This localized modification targets the problematic regions to eliminate display nonuniformity while maintaining the overall simplicity of the electrode structure

Inventive Principle:
Principle #3Local quality

2Manufacturing precision

If triangle cuts or apertures are formed in electrode patterns to cancel display nonuniformity, then display uniformity is improved, but electrode structure complexity increases

Engineering Contradiction:
Improvedisplay uniformityVSAvoidelectrode pattern structure
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the electrode pattern into sections with triangle cuts or apertures at specific locations. This segmentation approach allows the electrode structure to maintain overall simplicity while introducing localized modifications that effectively cancel display nonuniformity

Inventive Principle:
Principle #1Segmentation

3Illumination intensity

If mono-domain alignment is used to achieve uniform liquid crystal orientation, then viewing angle property is improved, but aperture ratio decreases due to additional alignment structures

Engineering Contradiction:
Improveviewing angle propertyVSAvoidaperture ratio
Core Design Contradiction:
Illumination intensityVSArea of stationary object

Solution Approach 1:

The patent extracts the alignment control function from traditional alignment structures and implements it through electrode pattern modifications. By forming triangle cuts or apertures in the electrodes, the patent achieves mono-domain alignment and improved viewing angle properties without adding separate alignment structures that would reduce aperture ratio

Inventive Principle:
Principle #2Taking out (Extraction)

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 cancels display nonuniformity within approximately 70 degrees clockwise or counterclockwise from the anti-viewing angle, achieving display uniformity similar to that observed from the best viewing angle, thereby enhancing image quality.

Implementation Method 1

the alignment process at the center of the pixel and those defined by the oblique electric field near the edges are opposite

Methodology Applied
Scientific EffectAlignment process:

Implementation Method 2

oblique electric fields generated between electrodes, leading to uneven liquid crystal molecule orientation

Methodology Applied
Scientific EffectOblique electric field: Electric Field

Implementation Method 3

control retardation of a liquid crystal layer Δnd (Δn: birefringence of liquid crystal material, d: a thickness of liquid crystal layer)

Methodology Applied
Scientific EffectBirefringence: Birefringence

Data Source

PatentEP2458429B1Liquid crystal display device
Publication Date: 2016.11.23 STANLEY ELECTRIC CO LTD
  • EP2458429B1 patent drawingFigure 1~2
  • EP2458429B1 patent drawingFigure 3~4D
  • EP2458429B1 patent drawingFigure 5A~5D

AI summary

A liquid crystal display device comprises a vertical alignment liquid crystal layer with a pretilt angle placed between a pair of the transparent substrates and first and second transparent electrodes, each intersection point of which forms a pixel. The liquid crystal display device is characterized in that at least one triangle cut is formed at an edge of each first transparent electrode forming one side of a pixel where an alignment direction of vertical alignment liquid crystal layer and a direction to which liquid crystal molecules are tilted by an oblique electric field at the edge of each first transparent electrode are opposite to each other.