Fluorescent Ink Light-Emitting Medium for Anti-Counterfeit Security
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Solution Overview
Problem
Current anti-counterfeit measures for valuable papers, such as cash vouchers and identity cards, are vulnerable to forgery due to potential color differences or thickness variations in fluorescent inks, which can be detected by the naked eye, compromising their security and ease of authentication.
Innovation Solution
A light-emitting medium with a substrate featuring a light-emitting image composed of a first and second fluorescent material area, where a protective layer is applied, emitting the same color when irradiated with specific wavelengths of invisible light, making it difficult to distinguish without a judging tool, and only visible under UV-A or UV-C light, ensuring the image remains hidden under visible light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple fluorescent inks with different emission characteristics are used to enhance anti-counterfeit security, then the difficulty of forgery increases, but color differences or thickness variations between the inks may cause the light-emitting image to be visible under visible light, compromising security
Solution Approach 1:
A protective layer is introduced as an intermediary component between the fluorescent inks and the environment. This protective layer contains a quenching agent that selectively interacts with excess fluorescent materials or ink components, preventing them from emitting light under visible light while maintaining the fluorescent emission characteristics under UV light. This resolves the contradiction by mediating the interaction between the fluorescent inks and visible light.
Solution Approach 2:
The patent utilizes parameter changes in the fluorescent materials' emission characteristics at different wavelengths. The fluorescent inks are selected to have specific emission spectra that overlap under UV light but are suppressed under visible light by the quenching agent. By changing the excitation wavelength parameter, the system achieves different optical behaviors that resolve the security visibility issue.
2Reliability
If a protective layer is added to control fluorescent emission, then the visibility control under different light conditions improves, but the structure becomes more complex
Solution Approach 1:
The protective layer is designed to perform multiple functions simultaneously: it protects the fluorescent inks from degradation, controls the emission visibility under different light conditions through the quenching agent, and provides a uniform surface. By making the protective layer multi-functional, the patent reduces the need for additional separate components, thereby limiting the increase in structural complexity.
3Reliability
If fluorescent inks are used to create hidden images, then security against forgery improves, but authentication requires specialized UV lighting equipment, reducing ease of verification
Solution Approach 1:
The patent employs color changes of the fluorescent materials under different excitation conditions. The fluorescent inks exhibit specific color emissions under UV light that are distinct from their appearance under visible light. This color change property allows authentication to be performed by observing the color characteristics under UV illumination, making the process more intuitive and easier to perform while maintaining high security.
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 enhances the security of valuable papers by making it difficult to forge the light-emitting image and allows for easy and prompt authentication by the naked eye without the need for specialized tools, as the image only appears under specific UV light conditions, preventing accidental detection.
Implementation Method 1
when invisible light within a first wavelength range is irradiated, the first fluorescent material and the second fluorescent material emit light of colors that are viewed as the same color with each other
Implementation Method 2
when invisible light within a second wavelength range is irradiated, the first fluorescent material and the second fluorescent material emit light of colors that are viewed as different colors from each other
Data Source
AI summary
A light-emitting medium including a light-emitting image having a pattern area formed on a substrate by using a first fluorescent ink containing a first fluorescent material, a background area formed on the substrate by using a second fluorescent ink containing a second fluorescent material, and a overcoat layer formed on the first fluorescent material of the pattern area and the second fluorescent material of the background area. The first fluorescent material is made of a fluorescent material which emits light of blue color when UV-A is irradiated, and emits light of red color when UV-C is irradiated. The second fluorescent material is made of a fluorescent material which emits light of blue color or light of a color that is viewed as the same color as the blue color when the UV-A is irradiated, and emits light of green color when the UV-C is irradiated.