Liquid Crystal Variable Polarizer Without Extra Polarizer Layers

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Solution Overview

Problem

Existing liquid crystal systems lack alternative electro-optical properties and require additional polarizers for functionality, leading to inefficiencies and complexity.

Innovation Solution

A liquid crystal optical system with a variable polarizer comprising transparent electrodes, an electroactive layer of twisted nematic liquid crystals, and dichroic dyes, which can switch between polarization states without additional polarizers, allowing for reversible and instantaneous switching.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If additional polarizers are used to achieve polarization control, then polarization functionality is improved, but device complexity increases

Engineering Contradiction:
Improvepolarization functionalityVSAvoidnumber of components
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines the functions of liquid crystal switching and polarization control into a single integrated device. The liquid crystal layer with dichroic dyes simultaneously performs both the electro-optical switching and the polarization modulation that would traditionally require separate polarizer components, thereby reducing device complexity while maintaining polarization functionality

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The liquid crystal device is designed to perform multiple functions: it acts as both the electro-optical switching element and the polarization controller. The same liquid crystal layer with incorporated dichroic dyes provides both the switchable optical properties and the polarization selection, making the device universal and eliminating the need for additional specialized components

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Productivity

If traditional liquid crystal systems are used, then basic optical switching is achieved, but switching time is prolonged

Engineering Contradiction:
Improveswitching speedVSAvoidswitching time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent modifies the physical and chemical parameters of the liquid crystal system by incorporating dichroic dyes and optimizing the liquid crystal material composition. These parameter changes enable faster molecular reorientation and thus reduce the switching time while maintaining the basic optical switching function

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If electroactive layer thickness is increased to improve optical density, then polarization control is enhanced, but transparency is reduced

Engineering Contradiction:
Improvepolarization controlVSAvoidtransparency
Core Design Contradiction:
Adaptability or versatilityVSIllumination intensity

Solution Approach 1:

The patent optimizes the thickness parameter of the electroactive layer to achieve the optimal balance between polarization control and transparency. By carefully selecting the layer thickness and adjusting the concentration of dichroic dyes, the system achieves effective polarization modulation while maintaining high light transmission

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The electroactive layer is designed as a composite material system containing liquid crystals and dichroic dyes in specific proportions. This composite structure allows the layer to simultaneously provide both polarization control capability and high transparency by leveraging the complementary properties of the constituent materials

Inventive Principle:
Principle #40Composite materials

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 system achieves efficient polarization control with minimal components, reducing switching time to seconds and maintaining high transparency with low blur, suitable for various applications including building and vehicle glazing.

Implementation Method 1

comprising an electro-controllable device by liquid crystals

Methodology Applied
Scientific EffectLiquid crystal electro-optical effect: Liquid Crystals

Implementation Method 2

with an electric field E2 between the first and second electrodes

Methodology Applied
Scientific EffectElectric field effect on liquid crystals: Electric Field

Implementation Method 3

dichroic dyes (in particular in the dissolved state, especially in the liquid crystals)

Methodology Applied
Scientific EffectDichroic absorption: Dichroic Filter

Data Source

PatentEP4413421B1Liquid-crystal optical system
Publication Date: 2026.02.18 SAINT GOBAIN VITRAGE SA
  • EP4413421B1 patent drawingFigure 1
  • EP4413421B1 patent drawingFigure 2~3
  • EP4413421B1 patent drawingFigure 4

AI summary

The invention relates to an optical system (1000) comprising an electrically controllable variable polariser (100) having variable polarisation by means of liquid crystals and dichroic dyes.