Composite Tungsten Oxide Near-Infrared Shielding Particles
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Solution Overview
Problem
Conventional near-infrared shielding materials face challenges such as color tone changes, high production costs, and complex film structures, and existing tungsten oxide fine particles do not efficiently meet market demands for high transmittance in the visible light region while effectively shielding near-infrared rays.
Innovation Solution
A near-infrared shielding material dispersion body using composite tungsten oxide fine particles with a hexagonal crystal structure and specific lattice constants, dispersed in a solid medium, which maintains high transmittance in the visible light region while efficiently shielding near-infrared rays, and a method for producing these particles involving mechanical pulverization and heat treatment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional near-infrared shielding materials (black pigments, metal vapor deposition) are used to achieve near-infrared shielding, then near-infrared shielding performance is improved, but visible light transmittance decreases and color tone changes occur
Solution Approach 1:
The patent segments the spectral shielding function by using composite tungsten oxide fine particles with specific crystal structures that selectively absorb near-infrared radiation while allowing visible light to pass through. This segmentation of spectral response resolves the contradiction between near-infrared shielding and visible light transmittance.
Solution Approach 2:
The patent changes the crystal structure parameter of tungsten oxide from conventional phases to a specific hexagonal crystal structure with defined lattice constants (a-axis: 3.77-3.83 Å, c-axis: 7.40-7.60 Å). This parameter change enables selective optical absorption properties that shield near-infrared while maintaining visible light transmittance, resolving the spectral trade-off contradiction.
2Object-affected harmful factors
If complex multilayer film structures (multiple dielectric films and tungsten oxide films) are used to achieve high visible light transmittance and near-infrared shielding, then optical performance is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent extracts the essential shielding function into a single layer of composite tungsten oxide fine particles with optimized crystal structure, eliminating the need for complex multilayer dielectric structures. This extraction principle simplifies the device while maintaining optical performance by focusing on the key functional material properties.
Solution Approach 2:
The patent uses composite tungsten oxide fine particles comprising multiple metal elements (W, Mo, Nb, Ta, V) in specific compositional ranges to achieve both high visible light transmittance and effective near-infrared shielding in a single layer, reducing structural complexity while maintaining dual optical functions.
3Ease of manufacture
If conventional tungsten oxide fine particles are used for near-infrared shielding, then production process is simplified, but near-infrared shielding efficiency and visible light transmittance performance are insufficient
Solution Approach 1:
The patent changes the crystal structure parameters of tungsten oxide to a specific hexagonal phase with precise lattice constants and compositional ratios of metal elements. This parameter optimization enables the material to achieve both high near-infrared shielding efficiency and high visible light transmittance, overcoming the performance limitations of conventional tungsten oxide particles while maintaining manufacturability.
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 achieves excellent optical properties with high transmittance in the visible light region and effective near-infrared shielding, outperforming conventional materials in both performance and production efficiency.
Implementation Method 1
the present invention relates to a near-infrared shielding material fine particle dispersion body, a near-infrared shielding body, and a near-infrared shielding laminated structure which are transparent in a visible light region and have absorption in a near-infrared region
Data Source
AI summary
A near-infrared shielding material fine particle dispersion body, a near-infrared shielding body, and a near-infrared shielding laminated structure containing composite tungsten oxide that exhibits more excellent near-infrared shielding function than that of a conventional near-infrared shielding material fine particle dispersion body, near-infrared shielding body, and near-infrared shielding laminated structure, and a method for producing the same. Also, a near-infrared shielding material fine particle dispersion body in which near-infrared shielding material fine particles are dispersed in a solid medium. The near-infrared shielding material fine particles are composite tungsten oxide fine particles containing a hexagonal crystal structure, in which a lattice constant of the composite tungsten oxide fine particles is 7.3850 Å or more and 7.4186 Å or less on the a-axis, and 7.5600 Å or more and 7.6240 Å or less on the c-axis, and a particle size of the near-infrared shielding material fine particles is 100 nm or less.