Electrophoretic Film with Insulating Electrodes for Stable Transmittance

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Solution Overview

Problem

Transmittance-variable films using electrophoretic phenomena face a reduction in transmittance and light shielding ratio due to particle adsorption on electrode layers when repeatedly switching between transparent and black modes.

Innovation Solution

Incorporating electrode insulating layers on the electrodes to prevent charged particle adsorption, maintaining constant transmittance in the transparent mode and enhancing light shielding in the black mode through the use of fluorine-based and acrylate resins, which reduce surface energy and facilitate particle dispersion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the transmittance-variable film is repeatedly driven between transparent mode and black mode, then the light shielding ratio is improved, but the transmittance is gradually reduced and particle dispersibility is lowered due to particle adsorption on the pattern electrode layer

Engineering Contradiction:

Improvelight shielding ratioVSAvoidtransmittance

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

An electrode insulating layer is introduced as an intermediary between the pattern electrode layer and the charged particles. This insulating layer prevents direct contact and adsorption between particles and the electrode, thereby maintaining particle dispersibility and stable transmittance in transparent mode while allowing the light shielding ratio to be improved through repeated operation.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The electrode structure is segmented into distinct functional layers: the pattern electrode layer for voltage application, the electrode insulating layer for particle isolation, and the electrophoretic layer for light control. This segmentation prevents particle adsorption on the electrode while maintaining the electrophoretic functionality.

Inventive Principle:

Principle #1Segmentation

2Reliability

If the transmittance-variable film is repeatedly driven between transparent mode and black mode, then the light shielding ratio is improved, but the dispersibility of charged particles is lowered due to particle adsorption on the pattern electrode layer

Engineering Contradiction:

Improvelight shielding ratioVSAvoidparticle dispersibility

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The electrode insulating layer serves as a mediator that prevents charged particles from adsorbing on the pattern electrode layer during repeated operation. This maintains particle dispersibility in the electrophoretic layer while enabling improved light shielding ratio through repeated switching between modes.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The electrode insulating layer converts the potentially harmful effect of particle adsorption on electrodes into a beneficial configuration where particles are confined to the electrophoretic layer, maintaining dispersibility while enabling repeated light shielding operation.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 maintains consistent transmittance in the transparent mode and achieves an excellent light shielding ratio in the black mode upon repeated switching, as evidenced by reduced transmittance in the black mode and increased light shielding efficacy.

Implementation Method 1

the electrophoretic layer may be equipped with charged particles in the form of particles capable of exhibiting an electrophoretic phenomenon by external force applied from the outside

Methodology Applied

Scientific EffectElectrophoretic phenomenon: Electrophoresis

Implementation Method 2

the use of fluorine-based and acrylate resins, which reduce surface energy and facilitate particle dispersion

Methodology Applied

Scientific EffectSurface energy reduction: Surface Tension

Data Source

PatentUS11619854B2Film having variable transmittance

Publication Date: 2023.04.04 LG CHEM LTD

AI summary

A transmittance-variable film, a use thereof, and a smart window including the same are disclosed herein. In some embodiments, a transmittance-variable film includes a first electrode substrate, a first electrode insulating layer disposed on the first electrode substrate, an electrophoretic layer, a second electrode insulating layer, and a second electrode insulating layer disposed on the second electrode substrate, wherein the first electrode substrate, the electrophoretic layer, and the second electrode substrate are sequentially arranged, and wherein the first and second electrode insulating layers contain a fluorine-based resin. Upon repeated driving of the film between a transparent mode and a black mode, the transmittance-variable film can maintain a transmittance constant in the transparent mode and exhibit an excellent light shielding ratio in the black mode.