Cholesteric Liquid Crystal Pigment Composition for Anti-Counterfeiting
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Solution Overview
Problem
Existing anti-counterfeit printed matters using cholesteric liquid crystal resins have limitations in authenticity determination due to improving counterfeiting techniques, necessitating an enhanced anti-counterfeit effect.
Innovation Solution
A pigment composition comprising a first cholesteric liquid crystal pigment with a center wavelength of 400 nm to 800 nm and a selective reflection bandwidth of 150 nm or less, and a second cholesteric liquid crystal pigment with a selective reflection bandwidth of 200 nm or more within the same wavelength range, used in a specific ratio to improve anti-counterfeit effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a cholesteric liquid crystal resin is used to create anti-counterfeit printed matter, then authenticity determination can be made with a simple device (naked-eye observation via circular polarizing plate), but the anti-counterfeit effect is insufficient due to improving counterfeiting techniques
Solution Approach 1:
The invention changes the optical parameters of the cholesteric liquid crystal pigments by specifying precise selective reflection bandwidth ranges (150-300 nm) and center wavelengths (400-800 nm). This parameter control creates a pigment composition where the first pigment's narrow bandwidth makes its color visually unrecognized under naked-eye observation, while the second pigment's wider bandwidth provides visible color, thereby enhancing anti-counterfeit reliability while maintaining ease of operation
Solution Approach 2:
The invention uses a composite pigment composition containing two different cholesteric liquid crystal pigments with distinct optical characteristics. The first pigment (narrow selective reflection bandwidth of 150-300 nm) and second pigment (wider selective reflection bandwidth) work together in specific weight ratios (5-50% and 50-95% respectively) to create an identification medium that is difficult to counterfeit while remaining observable with simple devices
2Reliability
If a pigment composition with specific first and second cholesteric liquid crystal pigments in specific ratios is used, then the color from the first pigment becomes visually unrecognized under naked-eye observation but recognizable under microscopic observation, improving anti-counterfeit effect, but the complexity of pigment composition increases
Solution Approach 1:
The invention manages pigment composition complexity by precisely controlling key parameters: selective reflection bandwidth (150-300 nm for first pigment, wider for second), center wavelength (400-800 nm), and weight ratios (first pigment 5-50%, second pigment 50-95%). These parameter specifications create a standardized composition that, while chemically complex, provides consistent and reliable anti-counterfeit performance that justifies the increased complexity
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 pigment composition enhances the anti-counterfeit effect by making the color from the first cholesteric liquid crystal pigment visually unrecognized under naked-eye observation but recognizable under microscopic observation, thereby improving authenticity determination.
Implementation Method 1
a first cholesteric liquid crystal pigment which has a center wavelength of a selective reflection band within a wavelength range of 400 nm or more and 800 nm or less, and a selective reflection bandwidth of 150 nm or less
Implementation Method 2
a second cholesteric liquid crystal pigment which has a selective reflection bandwidth of 200 nm or more within a wavelength range of 400 nm or more and 800 nm or less
Implementation Method 3
A cholesteric liquid crystal resin has a function of separating circularly polarized light that is a function of reflecting one of clockwise circularly polarized light and counterclockwise circularly polarized light, and allowing the other circularly polarized light to pass therethrough
Data Source
AI summary
A pigment composition including: a first cholesteric liquid crystal pigment; and a second cholesteric liquid crystal pigment, wherein: the first cholesteric liquid crystal pigment is a pigment having: a center wavelength of a selective reflection band within a wavelength range of 400 nm or more and 800 nm or less; and a selective reflection bandwidth of 150 nm or less; the second cholesteric liquid crystal pigment is a pigment having a selective reflection bandwidth of 200 nm or more within a wavelength range of 400 nm or more and 800 nm or less; the selective reflection band of the first cholesteric liquid crystal pigment and a selective reflection band of the second cholesteric liquid crystal pigment at least partially overlap with each other; and a containing amount of the first cholesteric liquid crystal pigment relative to a total amount of the first cholesteric liquid crystal pigment and the second cholesteric liquid crystal pigment is more than 0% by weight and 30% by weight or less.