Branched Pixel Electrode for Wide Viewing Angle

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Solution Overview

Problem

Liquid crystal displays face challenges in achieving a wide viewing angle and rapid response speed while maintaining a high open ratio, as existing designs often compromise on these factors due to the configuration of electrodes and liquid crystal molecule alignment.

Innovation Solution

The design incorporates a branched pixel electrode and a cross-shaped opening in the common electrode, along with a method to pretilt liquid crystal molecules using a polymerized prepolymer, to control the alignment and direction of liquid crystal molecules, enhancing viewing angle and response speed while increasing the open ratio.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If cutouts or openings are formed on the field generating electrode to ensure light viewing angle, then viewing angle is improved, but open ratio is decreased

Engineering Contradiction:
Improveviewing angleVSAvoidopen ratio
Core Design Contradiction:
Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The pixel electrode is divided into multiple branch electrodes extending in different directions, creating multiple tilt regions that disperse liquid crystal molecule tilt directions. This segmentation allows the electrode structure to control viewing angle without requiring additional cutouts that would reduce the open ratio

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the pixel electrode are designed with different orientations (branch electrodes in vertical, horizontal, and diagonal directions) to create localized tilt regions. Each region provides specific tilt control, and the combination achieves wide viewing angle while maintaining high open ratio by avoiding unnecessary openings

Inventive Principle:
Principle #3Local quality

2Speed

If liquid crystal molecules are aligned vertically in no electric field state (VA mode), then response speed is improved, but viewing angle is limited without additional cutouts

Engineering Contradiction:
Improveresponse speedVSAvoidviewing angle
Core Design Contradiction:
SpeedVSAdaptability or versatility

Solution Approach 1:

The pixel electrode is segmented into branch electrodes oriented in multiple directions, creating distinct tilt regions. This segmentation enables liquid crystal molecules to be tilted in different directions in different regions, achieving wide viewing angle while maintaining the vertical alignment baseline for fast response speed

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The branch electrodes are arranged asymmetrically in multiple directions (vertical, horizontal, diagonal) to create controlled asymmetry in liquid crystal tilt directions. This asymmetric arrangement disperses tilt directions to improve viewing angle while the underlying vertical alignment structure preserves rapid response characteristics

Inventive Principle:
Principle #4Asymmetry

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 results in improved transmittance and visibility, with increased viewing angle and response speed, and maintains high transmittance even at the edges of the pixel area, effectively addressing the limitations of previous designs.

Implementation Method 1

a method to pretilt liquid crystal molecules using a polymerized prepolymer

Methodology Applied
Scientific EffectPhotopolymerisation: Photopolymerisation

Implementation Method 2

The liquid crystal display generates electric fields 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 generated electric field

Methodology Applied
Scientific EffectElectric Field: Electric Field

Implementation Method 3

determines the direction of liquid crystal molecules of the liquid crystal layer by the generated electric field, thus controlling polarization of incident light so as to display images

Methodology Applied
Scientific EffectPolarisation: Polarisation

Data Source

PatentEP2520974B1Liquid crystal display
Publication Date: 2017.07.26 SAMSUNG DISPLAY CO LTD
  • EP2520974B1 patent drawingFigure 1
  • EP2520974B1 patent drawingFigure 2
  • EP2520974B1 patent drawingFigure 3

AI summary

A liquid crystal display according to an exemplary embodiment of the present invention includes a first substrate, a pixel electrode (191) disposed on the first substrate, a first alignment layer disposed on the first substrate and the pixel electrode, a second substrate facing the first substrate, a common electrode disposed on the second substrate, a second alignment layer disposed on the second substrate and the common electrode, and a liquid crystal layer disposed between the first substrate and the second substrate, in which the common electrode has a first opening (271) having a cross shape, an edge of the first opening protrudes beyond an edge of the pixel electrode (191), and the pixel electrode includes a second opening (91) disposed adjacently to at least one of the edges of the pixel electrode.