Hexagonal Tungsten Oxide Particles for NIR Shielding Transparency

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Solution Overview

Problem

Existing complex tungsten oxide particles lack sufficient visible light transparency and infrared ray shielding performance compared to known materials.

Innovation Solution

Complex tungsten oxide particles with a hexagonal crystal structure, represented by M x W y O z (where 0.20 ≤ x/y ≤ 0.37 and 2.2 ≤ z/y ≤ 3.3), having a controlled particle diameter of 800 nm or less, and specific W atom defects observed in STEM-HAADF images, enhance transparency and shielding performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If complex tungsten oxide particles are used for near-infrared ray shielding, then infrared ray shielding ability is improved, but visible light transparency deteriorates

Engineering Contradiction:
Improvenear-infrared ray shielding abilityVSAvoidvisible light transparency
Core Design Contradiction:
Object-affected harmful factorsVSIllumination intensity

Solution Approach 1:

The patent applies parameter changes by precisely controlling the compositional parameters (x, y, z in MxWyOz) within specific ranges (0.20≤x/y≤0.37, 2.2≤z/y≤3.3) to optimize the balance between infrared shielding and visible transparency. This systematic parameter optimization resolves the contradiction by finding the optimal composition point that simultaneously achieves both performance requirements

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces local quality by creating specific W atom defects (dark spots in STEM-HAADF images) within the crystal structure. These localized defects concentrate the infrared absorption capability in specific regions while maintaining the overall crystal structure integrity that enables visible light transparency, thus resolving the contradiction between shielding ability and transparency

Inventive Principle:
Principle #3Local quality

2Illumination intensity

If particle size is reduced to improve transparency, then visible light transparency is improved, but infrared ray shielding performance deteriorates

Engineering Contradiction:
Improvevisible light transparencyVSAvoidinfrared ray shielding performance
Core Design Contradiction:
Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

The patent applies parameter changes by establishing a specific particle size range (800 nm or less) that optimizes the balance between scattering of visible light and absorption of infrared rays. This size parameter optimization allows the particles to maintain transparency while preserving infrared shielding capability

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If synthesis time is extended to improve particle uniformity, then manufacturing precision is improved, but productivity deteriorates

Engineering Contradiction:
Improveparticle uniformityVSAvoidsynthesis time
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent applies parameter changes by optimizing the synthesis temperature range (400-700°C) and time parameters to achieve particle formation within 1-48 hours. This parameter optimization balances the need for uniform particle structure with production efficiency, resolving the contradiction between precision and productivity

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 solution provides complex tungsten oxide particles with improved visible light transparency and infrared ray shielding, maintaining high visibility while efficiently absorbing near-infrared rays.

Implementation Method 1

maintaining high visibility while efficiently absorbing near-infrared rays

Methodology Applied
Scientific EffectOptical absorption: Absorption (EM radiation)

Data Source

PatentEP4682107A1Complex tungsten oxide particles, near-infrared ray absorbing particle dispersion liquid, and near-infrared ray absorbing particle dispersion
Publication Date: 2026.01.21 SUMITOMO METAL MINING CO LTD
  • EP4682107A1 patent drawingFigure 1~2
  • EP4682107A1 patent drawingFigure 3~5
  • EP4682107A1 patent drawingFigure 6

AI summary

Complex tungsten oxide particles include complex tungsten oxide represented by a general formula: MxWyOz (where, the M element is at least one element selected from the group consisting of alkali metal elements, alkaline earth metal elements, rare earth elements, Mg, Zr, Cr, Mn, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Tl, Si, Ge, Sn, Pb, Sb, B, F, P, S, Se, Br, Te, Ti, Nb, V, Mo, Ta, Re, Be, Hf, Os, Bi, and I; W is tungsten; O is oxygen; 0.20 ≤ x/y ≤ 0.37; and 2.2 ≤ z/y ≤ 3.3). A crystal system of the complex tungsten oxide is hexagonal. An STEM-HAADF image observation of the complex tungsten oxide particles at [001] incidence includes a spot in a number ratio of 0.01% or greater and 10% or less, where the spot is a spot at which a value of a Z-contrast of tungsten atoms is reduced to be 95% or lower of an average value of the Z-contrast of tungsten atoms.