Liquid Crystal Composition for Optical Devices

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Solution Overview

Problem

In liquid crystal optical devices with a transmission/scattering operation mode, the high compatibility between liquid crystal and curable compounds leads to small liquid crystal domains, increased driving voltage, and issues with uncured curable compounds remaining, affecting quality and yield, and requires precise temperature control during production, making scaling up difficult.

Innovation Solution

A liquid crystal composition comprising a non-curable liquid crystal compound, a liquid crystalline curable compound with polymerizable functional groups, and a non-liquid crystalline curable compound with a higher content of the latter, ensuring compatibility and reducing domain size, with the total curable compounds making up at least 8-20 mass% of the composition, to form an electrooptical functional layer with improved properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a liquid crystalline curable compound and a liquid crystal compound are used as the liquid crystal composition, then compatibility of the liquid crystal composition is good, but the size of the liquid crystal domain tends to be small

Engineering Contradiction:

Improvecompatibility of liquid crystal compositionVSAvoidsize of liquid crystal domain

Core Design Contradiction:

Stability of the object's compositionVSVolume of moving object

Solution Approach 1:

The invention changes the chemical composition parameters by introducing a non-liquid crystalline curable compound with specific functional groups (acryloyl, methacryloyl, glycidyl, or allyl groups) into the liquid crystal composition. This compositional parameter change allows the system to achieve both good compatibility and appropriate liquid crystal domain size through controlled phase separation during curing.

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If the liquid crystal domain is small, then the liquid crystal optical device can be manufactured, but the driving voltage tends to rise

Engineering Contradiction:

Improvemanufacturability of liquid crystal optical deviceVSAvoiddriving voltage

Core Design Contradiction:

Ease of manufactureVSForce

Solution Approach 1:

The invention optimizes the size parameter of liquid crystal domains by controlling the phase separation process through the use of non-liquid crystalline curable compounds. By adjusting the composition and curing conditions, the invention achieves an optimal domain size that reduces the required driving voltage while maintaining manufacturability.

Inventive Principle:

Principle #35Parameter changes

3Stability of the object's composition

If high compatibility is used, then the liquid crystal composition is stable, but uncured curable compound remains and quality deteriorates

Engineering Contradiction:

Improvestability of liquid crystal compositionVSAvoidquality of liquid crystal optical device

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The invention utilizes phase transition during the curing process. The non-liquid crystalline curable compound undergoes phase separation from the liquid crystal phase during curing, enabling complete curing reaction while maintaining liquid crystal domain integrity. This phase transition mechanism eliminates uncured compound residue and improves device quality.

Inventive Principle:

Principle #36Phase transitions

4Manufacturing precision

If precise temperature control is required during production, then the quality is maintained, but scaling up becomes difficult

Engineering Contradiction:

Improvequality control during productionVSAvoidscalability of production

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The invention enables the liquid crystal composition to self-regulate during the curing process. The phase separation and curing reactions proceed with inherent temperature stability, reducing the need for external temperature control mechanisms. This self-service characteristic facilitates easy scaling up of production while maintaining quality.

Inventive Principle:

Principle #25Self-service

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 composition simplifies the production process, reduces driving voltage, and enhances the stability and impact resistance of the liquid crystal optical device, allowing for high-quality devices of various sizes without the need for precise temperature control during production.

Implementation Method 1

a liquid crystalline curable compound having a polymerizable functional group

Methodology Applied

Scientific EffectPhotopolymerization: Photopolymerisation

Data Source

PatentUS9976087B2Liquid crystal composition and liquid crystal optical device

Publication Date: 2018.05.22 AGC INC

AI summary

To provide a high quality liquid crystal optical device irrespective of the size of the liquid crystal optical device, while simplifying the production process, and a liquid crystal composition suitable for such a liquid crystal optical device. The liquid crystal composition of the present invention is a liquid crystal composition comprising a liquid crystal compound which shows liquid crystallinity and which is a non-curable compound, a liquid crystalline curable compound having a polymerizable functional group, and a non-liquid crystalline curable compound having a polymerizable functional group, wherein the content of the non-liquid crystalline curable compound is larger than the content of the liquid crystalline curable compound, and the total amount of the liquid crystalline curable compound and the non-liquid crystalline curable compound is at least 8 mass % and less than 20 mass % of the entirety.