Liquid Crystal Display Protrusions for Fast Response and Reliability

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Solution Overview

Problem

Liquid crystal displays face challenges in achieving high panel reliability and fast response speed while maintaining a wide viewing angle, particularly in vertically aligned modes and pretilt configurations.

Innovation Solution

Incorporating a polymer film with protrusions formed from a compound represented by Formula 1, which includes photo-reactive groups P1 and P2, between the substrates and the liquid crystal layer, allowing for photopolymerization to create a pretilt without the need for an alignment layer or reactive mesogen, enhancing the alignment and response speed of liquid crystal molecules.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a vertically aligned mode is used to achieve high contrast ratio and wide viewing angle, then display quality is improved, but response speed decreases

Engineering Contradiction:
Improvedisplay qualityVSAvoidresponse speed
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

The patent applies preliminary action by forming protrusions with pretilt angles before the liquid crystal molecules are aligned. These protrusions are created through photopolymerization of compounds with pretilt structures, which preliminarily set the desired alignment state. When voltage is applied, the liquid crystal molecules transition from this pre-configured state more rapidly, improving response speed while maintaining the vertical alignment benefits for contrast ratio and viewing angle.

Inventive Principle:
Principle #10Preliminary action

2Speed

If pretilt is introduced to increase response speed and viewing angle, then response speed is improved, but panel reliability deteriorates

Engineering Contradiction:
Improveresponse speedVSAvoidpanel reliability
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The patent uses composite materials by combining protrusions made from polymerized compounds (with pretilt structures) and liquid crystal materials. The protrusions serve as a structural framework that provides mechanical support and predetermined alignment guidance, while the liquid crystal molecules fill the spaces and provide the optically active function. This composite structure enhances panel reliability through the rigid protrusion framework while maintaining fast response speeds through the liquid crystal's electrotropic properties.

Inventive Principle:
Principle #40Composite materials

3Device complexity

If alignment layer is removed to simplify structure and reduce manufacturing steps, then device complexity is reduced, but alignment precision deteriorates

Engineering Contradiction:
Improvestructure complexityVSAvoidalignment precision
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent applies the extraction principle by removing the alignment layer from the conventional liquid crystal display structure. Instead of using a separate alignment layer to control liquid crystal orientation, the invention extracts this function and integrates it directly into the protrusion structures formed through photopolymerization. The protrusions themselves provide the alignment function through their geometric configuration and pretilt angles, eliminating the need for the alignment layer while maintaining precise alignment control.

Inventive Principle:
Principle #2Taking out (Extraction)

4Speed

If protrusions are formed to induce vertical alignment and pretilt, then response speed is improved, but manufacturing complexity increases

Engineering Contradiction:
Improveresponse speedVSAvoidmanufacturing complexity
Core Design Contradiction:
SpeedVSEase of manufacture

Solution Approach 1:

The patent replaces mechanical alignment methods (such as rubbing alignment layers or using mechanical pretilt structures) with a photochemical approach. By using photopolymerization of compounds containing pretilt structures, the alignment function is achieved through chemical bonding and molecular self-organization rather than mechanical processes. This substitution simplifies manufacturing by eliminating mechanical rubbing steps, reducing contamination risks, and enabling precise control through light exposure patterns.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 solution provides a liquid crystal display with improved panel reliability and fast response speed, as well as excellent after-image characteristics, by inducing vertical alignment and pretilt in liquid crystal molecules through photopolymerization, without requiring additional alignment layers or reactive mesogens.

Implementation Method 1

a polymer film having high hardness... the plurality of protrusions includes a polymer of a compound represented by Formula 1... allowing for photopolymerization to create a pretilt

Methodology Applied
Scientific EffectPhotopolymerization: Photopolymerisation

Data Source

PatentUS10620480B2Liquid crystal display
Publication Date: 2020.04.14 SAMSUNG DISPLAY CO LTD
  • US10620480B2 patent drawing
  • US10620480B2 patent drawing
  • US10620480B2 patent drawing

AI summary

A liquid crystal display includes: a first substrate; a second substrate overlapping the first substrate; a liquid crystal layer between the first substrate and the second substrate and including liquid crystal molecules; and a plurality of protrusions between the first substrate and the liquid crystal layer, between the second substrate and the liquid crystal layer, or a combination thereof, wherein the plurality of protrusions includes a polymer of a compound represented by Formula 1.