LCD Pixel Electrode Branch Design for Viewing Angle and Response Speed

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Solution Overview

Problem

Liquid crystal display devices with vertically aligned mode face challenges in maintaining wide viewing angles and response speed due to the formation of minute slits in pixel electrodes, which can lead to texture issues and delayed response times.

Innovation Solution

The design incorporates a partial plate electrode with a rhombus shape and minute branch electrodes that protrude from it, along with a common electrode featuring a cross structure with cutouts or protrusions, to improve liquid crystal molecule alignment and control, enhancing viewing angles and response speed by ensuring the ends of the branch electrodes are not connected, allowing for better electric field alignment without resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If minute slits are formed in the pixel electrode to secure wide viewing angle, then the viewing angle is improved, but the response speed of liquid crystal molecules decreases

Engineering Contradiction:
Improveviewing angleVSAvoidresponse speed
Core Design Contradiction:
ShapeVSSpeed

Solution Approach 1:

The pixel electrode is segmented into a cross-shaped structure with multiple minute branch electrodes extending from the center. This segmentation creates multiple independent tilt direction control points without requiring continuous slit patterns, thereby maintaining wide viewing angle while reducing the overall resistance to liquid crystal molecule rotation and improving response speed.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The electrode structure employs asymmetric minute branch electrodes with specific length ratios (0.5-2.0 times the width of the pixel electrode) and strategic positioning. This asymmetric design optimizes the electric field distribution to control liquid crystal molecule tilt directions more effectively, achieving wide viewing angle without excessive resistance that would slow response speed.

Inventive Principle:
Principle #4Asymmetry

2Shape

If minute slits are formed in the pixel electrode to determine tilt directions, then the viewing angle is improved, but texture is displayed for a predetermined time

Engineering Contradiction:
Improveviewing angleVSAvoidtexture display time
Core Design Contradiction:
ShapeVSLoss of time

Solution Approach 1:

By dividing the pixel electrode into discrete minute branch electrodes rather than continuous slits, the structure reduces the time required for liquid crystal molecules to reorient after voltage changes. The segmented design allows more uniform and faster molecular alignment, minimizing the persistence of texture artifacts.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention optimizes specific parameters including the length of minute branch electrodes (0.5-2.0 times the pixel electrode width) and their positioning relative to the pixel center. These parameter adjustments create optimal electric field gradients that accelerate liquid crystal molecule response and reduce texture display time.

Inventive Principle:
Principle #35Parameter changes

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 effectively widens the viewing angle, improves the response speed of liquid crystal molecules, and reduces texture issues by providing a controlled alignment force, resulting in improved display performance.

Implementation Method 1

The liquid crystal display device applies an electric field in the liquid crystal layer by applying voltage to the field generating electrodes, and determines the direction of liquid crystal molecules of the liquid crystal layer by the applied electric field

Methodology Applied
Scientific EffectElectric field: Electric Field

Implementation Method 2

controlling polarization of incident light so as to display images

Methodology Applied
Scientific EffectPolarization: Polarisation

Implementation Method 3

a vertically aligned mode liquid crystal display device of which liquid crystal molecules are aligned so that long axes thereof are vertical to the display panel while the electric field is not applied

Methodology Applied
Scientific EffectVertical alignment:

Implementation Method 4

Since cutouts and protrusions determine tilt directions of the liquid crystal molecules, the tilt directions of the liquid crystal molecules are dispersed in various directions by properly locating the cutouts and the protrusions

Methodology Applied
Scientific EffectTilt direction control:

Data Source

PatentEP2743759B1Liquid crystal display device
Publication Date: 2017.03.08 SAMSUNG DISPLAY CO LTD
  • EP2743759B1 patent drawingFigure 1
  • EP2743759B1 patent drawingFigure 2
  • EP2743759B1 patent drawingFigure 3

AI summary

A liquid crystal display device includes a lower panel having a lower substrate. A pixel electrode is formed on the lower substrate and includes a partial plate electrode and a plurality of minute branch electrodes extending from the partial plate electrode. A lower layer is formed on the lower substrate and below the pixel electrode and includes an inclined portion. An upper panel includes an upper substrate facing the lower substrate and a common electrode formed on the upper substrate. A liquid crystal layer is positioned between the lower panel and the upper panel, in which a part of the inclined portion is overlapped with a part of the minute branch electrode.