Liquid Crystal Light Control Sheet for Wide-Range Haze Stability

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Solution Overview

Problem

Conventional light control sheets experience issues with viscosity changes due to temperature fluctuations, leading to inconsistent haze levels and impaired functionality.

Innovation Solution

A liquid crystal-dispersed light control sheet with a resin composition containing a specific acrylic polymer structure and a liquid crystal compound with a nematic-isotropic phase transition temperature between 110°C and 140°C, promoting phase separation and compatibility across a wide temperature range.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional light control sheets are used in harsh temperature environments, then the light control sheet is exposed to temperature changes, but the viscosity of the light control layer becomes too high or too low, resulting in insufficient haze control

Engineering Contradiction:
Improvehaze control consistencyVSAvoidtemperature range
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The patent changes the chemical composition parameters of the resin by specifying a particular acrylic polymer structure (formula 1) with specific functional groups. This parameter change in the resin composition enables the material to maintain appropriate viscosity across a wide temperature range (-30°C to 100°C), resolving the contradiction between temperature variability and haze control consistency.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite system by combining the specifically structured acrylic polymer (formula 1) with liquid crystal composition. This composite material approach ensures that the resin maintains stable viscosity characteristics across extreme temperatures, allowing consistent haze control in both opaque and transparent states throughout the temperature range.

Inventive Principle:
Principle #40Composite materials

2Reliability

If the viscosity of the light control layer becomes too high due to temperature changes, then the light control sheet cannot achieve the required haze even when drive voltage is applied

Engineering Contradiction:
Improvehaze performanceVSAvoidtemperature effect on viscosity
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent modifies the resin composition parameters by incorporating the acrylic polymer with the specific structure in formula (1). This structural parameter change ensures the resin maintains optimal viscosity characteristics across temperature variations, preventing the harmful effect of excessive viscosity at low temperatures that would impede haze control performance.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the viscosity of the light control layer becomes too low due to temperature changes, then the light control sheet cannot maintain the required haze

Engineering Contradiction:
Improvehaze performanceVSAvoidtemperature effect on viscosity
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent adjusts the resin composition parameters by specifying the acrylic polymer structure in formula (1), which provides thermal stability to the viscosity. This parameter optimization prevents the harmful effect of excessively low viscosity at high temperatures, ensuring the light control layer maintains sufficient haze performance across the entire operating temperature range.

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 light control sheet maintains consistent haze levels between opaque and transparent states over a temperature range of -30°C to 100°C, ensuring reliable operation.

Implementation Method 1

the liquid crystal composition being composed of a liquid crystal compound having a nematic-isotropic phase transition temperature of 110°C or greater and 140°C or less

Methodology Applied
Scientific EffectNematic-isotropic phase transition: Phase Change

Implementation Method 2

the acrylate polymer and the liquid crystal compound can be phase-separated throughout the entire resin composition

Methodology Applied
Scientific EffectPhase separation:

Implementation Method 3

The orientation state of liquid crystal molecules changes depending on the potential difference between the two transparent electrode layers

Methodology Applied
Scientific EffectElectro-optic effect: Electro-Optic Effects

Data Source

PatentEP4318113B1Light control sheet, light control device, photosensitive composition, and method for manufacturing light control sheet
Publication Date: 2025.10.22 TOPPAN INC
  • EP4318113B1 patent drawingFigure 1~2
  • EP4318113B1 patent drawingFigure 3~4
  • EP4318113B1 patent drawingFigure 5

AI summary

A light control layer 11 containing a liquid crystal composition and a resin composition is provided, the liquid crystal composition is composed of a liquid crystal compound having a nematic-isotropic phase transition temperature of 110°C or greater and 140°C or less, the resin composition contains an acrylic polymer, a bridging group of the acrylic polymer is a saturated alkyl group having 1 or more and 12 or fewer carbon atoms, and the resin composition contains, in the acrylic polymer, a moiety in which the saturated alkyl group is a linear alkyl group, whereby a light control device operates normally over a wider temperature range.