Light-Diffusing Film Conductive Layer Radio Wave Transparency

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Solution Overview

Problem

Light control films used in vehicle windows and construction have low electrical resistance, leading to radio wave interference issues, such as malfunctioning televisions and mobile devices, and adhesiveness problems between transparent resin substrates and conductive layers.

Innovation Solution

A light control film configuration with a conductive polymer incorporated into an organic binder in the transparent conductive layer, using materials like polythiophene derivatives, polyaniline derivatives, and polypyrrole derivatives, and specific organic binder resins such as (meth)acrylates with hydroxyl groups or urethane acrylates with pentaerythritol skeletons, to achieve improved radio wave transparency and adhesiveness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a transparent conductive layer with low electrical resistance is used in light control films, then the light control function is improved, but radio wave interference occurs causing devices to malfunction

Engineering Contradiction:
Improvelight control functionVSAvoidradio wave interference
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent uses a composite material structure combining transparent resin substrate, transparent conductive layer, and light control suspension. The transparent conductive layer contains conductive particles (metal, metal oxide, or carbon-based) dispersed in a transparent resin, creating a composite that balances electrical conductivity for light control with radio wave transparency to prevent interference with electronic devices

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent applies different material properties to different layers: the transparent conductive layer has localized electrical conductivity for light control function, while maintaining overall radio wave transparency. The conductive particles are distributed specifically in the conductive layer rather than throughout the entire film, allowing localized functionality without global interference

Inventive Principle:
Principle #3Local quality

2Reliability

If a transparent conductive layer is applied to transparent resin substrates, then the light control function is enhanced, but adhesiveness problems occur between the substrate and conductive layer

Engineering Contradiction:
Improvelight control functionVSAvoidadhesiveness
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent uses a transparent resin as an intermediary bonding layer between the substrate and the conductive particles. This resin matrix provides adhesive bonding while maintaining transparency, allowing the conductive particles to be dispersed and fixed firmly in place without direct metal-to-substrate contact that would cause adhesion failures

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The transparent conductive layer is formed as a composite material with transparent resin and conductive particles. The resin component provides adhesion to the substrate while the conductive particles provide electrical conductivity, creating a multi-functional layer that solves both the light control function and adhesiveness requirements

Inventive Principle:
Principle #40Composite materials

3Reliability

If conventional light control glass with liquid suspension is used, then the light control function is achieved, but particle aggregation and sedimentation occur

Engineering Contradiction:
Improvelight control functionVSAvoidparticle dispersion stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent changes the physical state of the light control suspension from liquid to solid by embedding it in a cured resin matrix. This parameter change from liquid to solid phase prevents particle aggregation and sedimentation that occur in liquid suspensions, while maintaining the light control function through the solidified suspension structure

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent performs preliminary mixing of light control particles with uncured resin, then cures the mixture to lock particles in place before any aggregation or sedimentation can occur. This preliminary action of fixing particles in the resin matrix prevents the stability problems that would develop over time in liquid suspensions

Inventive Principle:
Principle #10Preliminary action

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 provides excellent radio wave transparency, allowing devices to function properly and enhances the adhesiveness between the transparent resin substrate and the conductive layer, addressing the interference and adhesion issues in existing light control films.

Implementation Method 1

the transparent conductive layer contains: an organic binder resin; and a conductive polymer

Methodology Applied
Scientific EffectElectrical Conductivity: Conduction (electrical)

Implementation Method 2

when an electric field is not applied, as a result of the Brownian motion of light control particles that are dispersed in the suspension, most of the incident light rays are reflected, scattered or absorbed by the light control particles

Methodology Applied
Scientific EffectLight scattering: Scattering

Implementation Method 3

when an electric field is not applied, as a result of the Brownian motion of light control particles that are dispersed in the suspension

Methodology Applied
Scientific EffectBrownian motion: Brownian Motion

Implementation Method 4

When an electric field is applied to a light control window which uses a light control glass having the above-described structure, an electric field is formed in the light control suspension through the transparent conductive substrates, and the light control particles that exhibit a light control function cause polarization and are arranged in parallel to the electric field

Methodology Applied
Scientific EffectPolarization: Polarisation

Data Source

PatentEP2530517B1Light-diffusing film
Publication Date: 2019.02.27 RESONAC CORP
  • EP2530517B1 patent drawingFigure 1~2(b)
  • EP2530517B1 patent drawingFigure 3(a)~4
  • EP2530517B1 patent drawingFigure 5~6

AI summary

Disclosed is a light control film comprising: two of transparent conductive resin substrates each having a transparent conductive layer and a transparent resin substrate; and a light control layer interposed between the two transparent conductive resin substrates to be in contact with the transparent conductive layer sides, the light control layer containing: a resin matrix; and a light control suspension dispersed in the resin matrix, wherein the transparent conductive layer contains: an organic binder resin; and a conductive polymer. The present invention can provide a light control film having satisfactory adhesiveness between the light control layer and the transparent conductive layer and having excellent radio wave transparency.