Asymmetric Pixel Electrode Geometry for LCD Fringe Field Reduction

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Solution Overview

Problem

In liquid crystal display (LCD) devices, the fringe field at the edge of pixel electrodes can misalign liquid crystal molecules, leading to degraded display quality and reduced viewing angles, especially when pixel electrodes have a quadrangular shape.

Innovation Solution

The design of pixel electrodes with a first stem portion, a second stem portion intersecting the first, diagonal branch portions, a bent portion, a connecting portion, and an edge bar, which reduce the fringe field effect by specific geometric configurations and spacings, improving liquid crystal control and display quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If pixel electrodes have a quadrangular shape, then manufacturing is simple, but the fringe field misaligns liquid crystal molecules degrading display quality and viewing angles

Engineering Contradiction:
Improvepixel electrode fabrication simplicityVSAvoidliquid crystal alignment precision
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The pixel electrode is designed with an asymmetric shape featuring a main body region and a protruding region that extends toward the common electrode. This asymmetric geometry modifies the electric field distribution to reduce the fringe field effect at edges, thereby improving liquid crystal alignment without complicating the manufacturing process

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The invention introduces a protruding region that extends in a direction toward the common electrode, adding a dimensional feature to the otherwise planar pixel electrode. This three-dimensional geometric modification creates a more favorable electric field profile that reduces edge effects while maintaining manufacturing simplicity

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Device complexity

If pixel electrodes have a quadrangular shape, then device structure is simple, but viewing angles are reduced due to fringe field effects

Engineering Contradiction:
Improvepixel electrode structureVSAvoidviewing angle range
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

By introducing asymmetry through the protruding region, the electric field distribution is optimized to minimize fringe field effects that limit viewing angles. This maintains structural simplicity while expanding viewing angle performance

Inventive Principle:
Principle #4Asymmetry

3Manufacturing precision

If pixel electrodes use standard geometric shapes, then manufacturing precision is easy to control, but liquid crystal alignment at edges is degraded

Engineering Contradiction:
Improveelectrode geometry controlVSAvoidfringe field effect
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The pixel electrode is segmented into a main body region and a protruding region, allowing different functional zones within a single electrode structure. The protruding region specifically addresses edge field effects while the main body maintains standard geometric control for manufacturing precision

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The protruding region is strategically positioned to create localized electric field modifications at the edges where fringe field effects occur. This local geometric adjustment targets the harmful edge effects without changing the overall electrode geometry, maintaining manufacturing precision while eliminating the harmful factor

Inventive Principle:
Principle #3Local quality

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 described geometric configuration of pixel electrodes enhances liquid crystal alignment and control at the edge, thereby improving the display quality and viewing angles of LCD devices.

Implementation Method 1

Upon applying a voltage to the pixel electrode and the common electrode, liquid crystal molecules of the liquid crystal layer are rearranged

Methodology Applied
Scientific EffectElectric field: Electric Field

Data Source

PatentEP3229065B1Display substrate and liquid crystal display device comprising the same
Publication Date: 2022.10.26 SAMSUNG DISPLAY CO LTD
  • EP3229065B1 patent drawingFigure 1
  • EP3229065B1 patent drawingFigure 2
  • EP3229065B1 patent drawingFigure 3~4

AI summary

A display substrate includes a base substrate having a plurality of pixel areas and a pixel electrode in a pixel area of the plurality of pixel areas. The pixel electrode a first stem portion extending in a first direction, a second stem portion extending from the first stem portion in a second direction that intersects the first direction, a plurality of branch portions diagonally extending from at least one of the first stem portion and the second stem portion, and a bent portion extending from at least one of the plurality of branch portions.