Electrochromic Dimming Layer Thickness and Ratio Control

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Solution Overview

Problem

Existing dimming devices using electrochromic materials suffer from persistent coloring phenomena and bubble occurrence due to oxidation-reduction reactions, which affect the transmittance and performance of the dimming layer.

Innovation Solution

The dimming device is designed with specific ratios of reduction and oxidation coloring layers, using materials like tungsten oxide and iridium tin oxide, and includes a moisture-retaining member to suppress coloring and bubble phenomena, ensuring uniformity and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If a dimming layer containing electrochromic material is used to change light transmittance through oxidation-reduction reactions, then the light transmittance can be adjusted, but a coloring phenomenon occurs where a coloring state is left in the dimming layer even when voltage is not applied

Engineering Contradiction:
Improvelight transmittanceVSAvoidcoloring phenomenon
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The patent applies parameter changes by carefully controlling the thickness of the reduction coloring layer and oxidation coloring layer, and by adjusting the atomic ratio of metals in these layers. Specifically, the reduction coloring layer thickness is set to 0.5-5.0 μm and the oxidation coloring layer thickness to 0.1-1.0 μm, with the metal atomic ratio controlled within specific ranges. These parameter optimizations enable the dimming layer to achieve desired light transmittance adjustment while minimizing residual coloring effects when voltage is not applied.

Inventive Principle:
Principle #35Parameter changes

2Illumination intensity

If a dimming layer containing electrochromic material repeats coloring and decoloring, then light transmittance can be dynamically adjusted, but a bubble occurrence phenomenon happens in the dimming layer

Engineering Contradiction:
Improvelight transmittanceVSAvoidbubble occurrence phenomenon
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The patent employs parameter changes by optimizing the thickness of the dimming layer (0.5-5.0 μm for reduction coloring layer, 0.1-1.0 μm for oxidation coloring layer) and controlling the metal atomic ratios within specific ranges. These parameter adjustments reduce the intensity of oxidation-reduction reactions, thereby suppressing bubble generation during repeated coloring and decoloring cycles while maintaining effective light transmittance control.

Inventive Principle:
Principle #35Parameter changes

3Illumination intensity

If the dimming layer undergoes oxidation-reduction reactions to change transmittance, then dynamic light control is achieved, but the coloring and bubble phenomena reduce the uniformity and stability of the dimming layer

Engineering Contradiction:
Improvelight transmittanceVSAvoiduniformity and stability
Core Design Contradiction:
Illumination intensityVSStability of the object's composition

Solution Approach 1:

The patent applies parameter changes by precisely controlling the thickness of the reduction coloring layer (0.5-5.0 μm) and oxidation coloring layer (0.1-1.0 μm), and by optimizing the metal atomic ratios within specific ranges. These parameter optimizations ensure uniform distribution of electrochromic materials and stabilize the chemical composition, thereby maintaining dimensional stability and preventing aggregation or precipitation during repeated oxidation-reduction reactions.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials by combining reduction coloring layer containing metal compounds (such as tungsten oxide, molybdenum oxide) with oxidation coloring layer containing different metal compounds (such as iridium oxide, ruthenium oxide). This composite structure leverages the complementary properties of different materials to achieve stable and uniform oxidation-reduction reactions, improving overall dimensional stability and preventing material degradation during cyclic operation.

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 solution effectively minimizes coloring and bubble issues, maintaining consistent transmittance and enhancing the reliability and visibility of the dimming device.

Implementation Method 1

a coloring phenomenon in which a coloring state is left a little in the dimming layer even in a state where voltage is not applied to the dimming layer and a bubble occurrence phenomenon in which bubbles occur in the dimming layer while the dimming layer repeats coloring and decoloring

Methodology Applied
Scientific EffectOxidation-reduction reaction: Redox Reactions

Implementation Method 2

a dimming layer (720) having a stacked structure of a reduction coloring layer (721), an electrolyte layer (722), and an oxidation coloring layer (723)

Methodology Applied
Scientific EffectElectrochromism: Electrochromism

Implementation Method 3

includes a moisture-retaining member to suppress coloring and bubble phenomena, ensuring uniformity and stability

Methodology Applied
Scientific EffectMoisture retention:

Data Source

PatentEP3712693B1Light control device, image display device, and display device
Publication Date: 2025.04.02 SONY GROUP CORP
  • EP3712693B1 patent drawingFigure 1A~1B
  • EP3712693B1 patent drawingFigure 2A~2C
  • EP3712693B1 patent drawingFigure 3A~3B

AI summary

A dimming device includes a first substrate 711, a second substrate 712, and a light emitting stacked body; the light emitting stacked body includes a first electrode 731, a dimming layer 720, and a second electrode 732 that are stacked; the dimming layer 720 has a stacked structure of a reduction coloring layer 721, an electrolyte layer 722, and an oxidation coloring layer 723; when the number of atoms of a metal contributing to reduction reaction in a compound contained in the reduction coloring layer 721 is denoted by [Re] and the number of atoms of a metal contributing to oxidation reaction in a compound contained in the oxidation coloring layer 723 is denoted by [Ox], the value of [Re]/[Ox] is within a prescribed range; alternatively, when the thickness of the reduction coloring layer 721 is denoted by TRe and the thickness of the oxidation coloring layer 723 is denoted by TOx, the value of TRe/TOx is within a prescribed range.