LCD Pixel Electrode Protrusions for Texture Control

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Solution Overview

Problem

In liquid crystal displays (LCDs), external forces can cause abnormal arrangements of liquid crystal molecules, particularly around contact holes, leading to texture and luminance variations that degrade display quality, especially in high-resolution screens where pixel size is small and the texture region increases, making abnormal arrangements more noticeable.

Innovation Solution

The implementation of a liquid crystal display with a substrate having a light transmitting region and a light blocking region, featuring a thin film transistor in the light blocking region, a pixel electrode connected through a contact hole, and protruding portions on the pixel electrode with a stem and branch structure that extends into the light blocking region, helping to realign liquid crystal molecules and prevent abnormal arrangements from propagating to the light transmitting region.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If external force is applied to the liquid crystal display, then the liquid crystal molecules are disarranged to generate texture, but the liquid crystal molecules around the contact hole remain abnormal even after the external force is removed

Engineering Contradiction:
Improveliquid crystal molecule arrangement stabilityVSAvoidabnormal arrangement of liquid crystal molecules
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The protruding portion is formed in advance on the pixel electrode before liquid crystal molecules are filled. This pre-formed structure serves as a guide to prevent abnormal arrangement of liquid crystal molecules around the contact hole, ensuring they align properly even after external forces are applied and removed.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The protruding portion acts as an intermediary structure between the contact hole and the liquid crystal molecules. It mediates the interaction by providing a physical guide that directs liquid crystal molecules into proper alignment, preventing the transmission of abnormal arrangements from the contact hole region to the light transmitting region.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If the insulating layer includes organic material, then the step of the contact hole increases, but it becomes more difficult to restore the liquid crystal molecules to their original arrangement

Engineering Contradiction:
Improveinsulating layer material selectionVSAvoidliquid crystal molecule alignment
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The protruding portion is formed on the pixel electrode before liquid crystal injection. This pre-formed structure compensates for the large step difference caused by organic insulating layer material, providing a guide that ensures proper liquid crystal alignment despite the increased step height.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If the LCD has higher resolution, then the pixel size is smaller, but the ratio of texture region in the light transmitting region increases, degrading display quality

Engineering Contradiction:
Improvedisplay resolutionVSAvoiddisplay quality
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The protruding portion is strategically positioned around the contact hole within the pixel electrode, providing localized alignment control precisely where abnormal arrangements originate. This local intervention prevents texture propagation to the light transmitting region while maintaining high resolution display quality.

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

This design effectively reduces the propagation of abnormal liquid crystal molecule arrangements to the light transmitting region, thereby improving display quality by maintaining the original alignment and reducing texture and luminance variations, especially in high-resolution displays.

Implementation Method 1

a liquid crystal layer having dielectric anisotropy

Methodology Applied
Scientific EffectDielectric anisotropy: Dielectric Permittivity

Implementation Method 2

applying voltages to the pixel electrodes and the opposing electrodes to generate an electric field in the liquid crystal layer

Methodology Applied
Scientific EffectElectric field: Electric Field

Implementation Method 3

a protruding portion disposed on the pixel electrode, wherein the pixel electrode includes: a stem portion disposed in the light transmitting region; a plurality of branch portions connected to the stem portion; and an extension disposed in the light blocking region

Methodology Applied
Scientific EffectMolecular alignment:

Data Source

PatentEP3048477B1Liquid crystal display
Publication Date: 2019.02.27 SAMSUNG DISPLAY CO LTD
  • EP3048477B1 patent drawingFigure 1
  • EP3048477B1 patent drawingFigure 2
  • EP3048477B1 patent drawingFigure 3

AI summary

A liquid crystal display (LCD) includes: a substrate including a light transmitting region and a light blocking region; a thin film transistor disposed in the light blocking region, the thin film transistor including a source electrode, a drain electrode, and a gate electrode; a first insulating layer disposed on the drain electrode, the first insulating layer including a contact hole for exposing the drain electrode; a pixel electrode disposed on the first insulating layer, the pixel electrode connected to the drain electrode through the contact hole; and a protruding portion disposed on the pixel electrode, wherein the pixel electrode includes: a stem portion disposed in the light transmitting region; a plurality of branch portions connected to the stem portion; and an extension disposed in the light blocking region, the extension configured to extend from the stem portion or the branch portions, and wherein the protruding portion overlaps the extension.