Anti-Counterfeit Ink Composition With Tungsten Oxide NIR Contrast
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Solution Overview
Problem
Existing anti-counterfeit inks using composite tungsten oxide fine particles exhibit insufficient near-infrared absorption properties and insufficient contrast between visible light and near-infrared regions, and are lacking in weather resistance.
Innovation Solution
The anti-counterfeit ink composition utilizes composite tungsten oxide fine particles with a specific lattice constant range (a-axis: 7.3850 Å to 7.4186 Å, c-axis: 7.5600 Å to 7.6240 Å) and a hexagonal crystal structure, coated with elements like Si, Ti, Al, or Zr, and dispersed in a solvent or resin, to enhance near-infrared absorption and maintain visible light transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If phthalocyanine compounds are used as near-infrared absorbing materials, then near-infrared absorption is achieved, but weather resistance deteriorates due to reduced absorption properties under temperature and ultraviolet influence
Solution Approach 1:
The patent changes the material parameter from phthalocyanine compounds to tungsten oxide fine particles, which have different optical and chemical properties. Tungsten oxide maintains stable absorption properties under temperature and UV exposure, resolving the weather resistance issue while preserving near-infrared absorption capability
Solution Approach 2:
The patent uses composite tungsten oxide fine particles with specific crystal structures and compositions. By controlling the crystal phase and particle characteristics, the material achieves both excellent near-infrared absorption and superior weather resistance, overcoming the limitations of single-material approaches
2Use of energy by moving object
If solar radiation absorbing film is applied to anti-counterfeit ink, then near-infrared absorption is achieved, but contrast between absorption and transmission regions deteriorates, reducing reading precision
Solution Approach 1:
The patent applies local quality by creating tungsten oxide fine particles with specific local crystal structures and surface properties. The particles exhibit high near-infrared absorption in specific wavelength regions while maintaining transparency in visible light regions, achieving superior contrast essential for precise reading and authentication
Solution Approach 2:
The patent optimizes critical parameters including particle size (1-100 nm), crystal structure (monoclinic, tetragonal, or cubic phases), and surface characteristics of tungsten oxide. These parameter adjustments maximize the contrast between near-infrared absorption and visible light transmission, enabling high reading precision
3Use of energy by moving object
If conventional near-infrared absorbing materials are used, then infrared absorption is achieved, but contrast between visible light transmission and near-infrared absorption is insufficient
Solution Approach 1:
The patent systematically optimizes multiple parameters of tungsten oxide fine particles including particle size (1-100 nm), crystal phase composition, stoichiometry (WO3-x where 0 < x < 0.3), and surface area. These parameter changes create material properties that simultaneously achieve high near-infrared absorption coefficient and high visible light transmission, maximizing the contrast ratio
Solution Approach 2:
The patent employs composite tungsten oxide structures with controlled phases and compositions. The composite nature at the nanoscale allows tuning of optical properties to achieve exceptional contrast between visible and near-infrared regions, outperforming conventional single-phase 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 provides an anti-counterfeit printed matter with reliable authenticity judgment, high weather resistance, and improved contrast between visible light and near-infrared regions, making it difficult to duplicate by copying and ensuring high productivity.
Implementation Method 1
a printing ink that absorbs near infrared rays having a wavelength from 800 to 2400 nm with little absorption in a visible light region of a wavelength of 300 to 780 nm
Implementation Method 2
transmit the visible light region and having absorption in the near-infrared region
Data Source
AI summary
There is provided an anti-counterfeit ink composition, an anti-counterfeit ink, and an anti-counterfeit printed matter that transmits a visible light region, having absorption in an infrared region, and capable of judging authenticity of a printed matter, and containing composite tungsten oxide fine particles, the composite tungsten oxide fine particles having a hexagonal crystal structure, having a lattice constant such that a-axis is 7.3850 Å or more and 7.4186 Å or less, and c-axis is 7.5600 Å or more and 7.6240 Å or less, and having a particle size of the near-infrared absorbing material fine particles is 100 nm or less, and a method for producing the anti-counterfeit ink composition, the anti-counterfeit ink, the anti-counterfeit printed matter, and the anti-counterfeit ink composition.