Liquid-Crystal Medium Composition for VA and FFS Contrast

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Solution Overview

Problem

Existing liquid crystal displays face challenges such as strong viewing-angle dependence of contrast, occurrence of mura, slow response times, and limited contrast ratio, particularly in VA, FFS, and PSA displays, which are unsuitable for modern display trends requiring high transmission, fast response times, and improved contrast.

Innovation Solution

A liquid crystal medium comprising specific compounds of formula I, which provide high clearing point, high average elastic constant, low birefringence, and low rotational viscosity, enhancing display properties like high contrast ratio, fast response times, and energy efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If conventional liquid crystal media are used in VA displays, then the LC molecules can be aligned perpendicular to the electrode surfaces, but the viewing angle dependence of contrast remains strong

Engineering Contradiction:

Improvealignment stabilityVSAvoidviewing angle dependence

Core Design Contradiction:

Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The patent introduces compounds with specific molecular structures (formula I) that have particular length-to-width ratios and functional groups, changing the physical parameters of the LC medium to achieve both perpendicular alignment and reduced viewing angle dependence

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite LC medium by combining compounds of formula I with other LC compounds in specific ratios, achieving synergistic effects that simultaneously provide stable perpendicular alignment and improved viewing angle characteristics

Inventive Principle:

Principle #40Composite materials

2Stability of the object's composition

If liquid crystal media with negative dielectric anisotropy are used in FFS displays, then planar alignment can be achieved, but the response time becomes slow

Engineering Contradiction:

Improvealignment uniformityVSAvoidresponse time

Core Design Contradiction:

Stability of the object's compositionVSSpeed

Solution Approach 1:

The patent modifies the molecular structure parameters of the LC compounds (formula I) to optimize the balance between dielectric anisotropy and rotational viscosity, enabling both planar alignment stability and fast response times in FFS displays

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent introduces compounds with specific local molecular structures (formula I) that have particular properties for interacting with the alignment layer, creating localized effects that improve overall alignment uniformity without sacrificing response speed

Inventive Principle:

Principle #3Local quality

3Illumination intensity

If liquid crystal media with high birefringence are used, then the transmission increases, but the contrast ratio decreases

Engineering Contradiction:

ImprovetransmissionVSAvoidcontrast ratio

Core Design Contradiction:

Illumination intensityVSManufacturing precision

Solution Approach 1:

The patent optimizes the birefringence parameter of the LC medium by selecting compounds of formula I with specific molecular structures, achieving a balanced value that provides sufficient transmission while maintaining high contrast ratio through optimized optical anisotropy

Inventive Principle:

Principle #35Parameter changes

4Reliability

If conventional liquid crystal media are used, then the display can operate, but the power consumption is high

Engineering Contradiction:

Improveoperational stabilityVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent changes the dielectric and viscosity parameters of the LC medium using compounds of formula I, enabling operation at lower voltages and reducing the energy required for switching, thereby decreasing power consumption while maintaining operational stability

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

The medium achieves improved display performance with high contrast ratio, fast response times, reduced power consumption, and enhanced reliability, addressing the limitations of current LC media in VA, FFS, and PSA displays.

Implementation Method 1

the LC medium usually has a negative dielectric anisotropy... On application of an electrical voltage to the two electrodes, a realignment of the LC molecules parallel to the electrode surfaces takes place

Methodology Applied

Scientific EffectDielectric anisotropy: Dielectric Permittivity

Implementation Method 2

The medium preferably has negative dielectric anisotropy and a birefringence, Δn, of 0.05 to 0.20, in particular 0.07 to 0.15, at 20°C and 589 nm

Methodology Applied

Scientific EffectBirefringence: Birefringence

Data Source

PatentEP4617343A1Liquid-crystal medium

Publication Date: 2025.09.17 MERCK PATENT GMBH

AI summary

The present invention relates to a liquid-crystal (LC) medium or liquid-crystal (LC) materials based on a mixture of polar compounds, to its use for optical, electro-optical and electronic purposes, in particular in LC displays, especially in LC displays of the vertically aligned mode and/or the fringe-field switching mode, to an LC display of the vertically aligned mode and/or the fringe-field switching mode comprising the LC medium, especially an energy-efficient LC display and to a process of manufacturing the LC display.