Luminescent Security Inclusions for Multi-UV Color Authentication
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Solution Overview
Problem
Security documents face challenges in authentication due to the variability in light emission colors of luminescent materials under different ultraviolet wavelengths, making verification difficult and susceptible to counterfeiting.
Innovation Solution
Incorporation of security inclusions with luminescent regions that emit distinct colors under different ultraviolet wavelengths, providing a striking visual effect and simplifying authentication by observing color changes with wavelength shifts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If luminescent materials are used in security documents to emit visible light under ultraviolet illumination, then the security feature becomes visible and detectable, but the color emitted varies with ultraviolet wavelength making verification problematic and susceptible to counterfeiting
Solution Approach 1:
The patent applies color changes by using luminescent materials that emit different colors at different ultraviolet wavelengths. Specifically, the security feature contains materials that emit blue-cyan light at 380-420nm, green-yellow light at 420-480nm, and yellow-orange light at 480-530nm. This wavelength-dependent color emission provides a reliable authentication mechanism while maintaining simple verification procedures, as the color sequence serves as a distinctive fingerprint for genuine documents.
2Reliability
If luminescent materials are used to provide security features, then authentication capability is enhanced, but the burden on counterfeiters is not sufficiently increased due to the ease of simulating single-color emission
Solution Approach 1:
The patent applies parameter changes by utilizing multiple luminescent materials with distinct emission characteristics at different ultraviolet wavelengths. The security feature contains a combination of materials including strontium aluminate doped with europium and dopant deficiencies, calcium aluminate doped with europium and dopant deficiencies, and other phosphors that exhibit specific emission spectra. This multi-parameter approach (wavelength, color, intensity ratios) creates a complex authentication signature that is difficult for counterfeiters to replicate, thereby significantly increasing the burden on would-be counterfeiters while enhancing security reliability.
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
Enhances authentication reliability and increases the burden on counterfeiters by creating a difficult-to-reproduce visual effect, ensuring robust and easier verification of security documents.
Implementation Method 1
the first luminescent region emitting visible light of (i) a first colour when viewed under ultraviolet light of a first wavelength and (ii) a second, different, colour when viewed under ultraviolet light of a second, different, wavelength
Implementation Method 2
the second luminescent region emitting visible light of a different colour to the first luminescent region when viewed under ultraviolet light of the first wavelength and/or emitting visible light of a different colour to the first luminescent region when viewed under ultraviolet light of the second wavelength
Data Source
Figure 1(a)~1(b)
Figure 2(a)~2(b)
Figure 3(a)~3(b)
AI summary
An inclusion (2) for incorporation into a security paper substrate (92) is disclosed. The inclusion (2) comprises a substrate (4); a first luminescent region (6) on a first and/or second side of the substrate (4), the first luminescent region (6) emitting visible light of (i) a first colour when viewed under ultraviolet light of a first wavelength and (ii) a second, different, colour when viewed under ultraviolet light of a second, different, wavelength. The substrate (4) also comprises a second luminescent region (8) on the first and/or second side of the substrate, the second luminescent region (8) emitting visible light of a different colour to the first luminescent region (6) when viewed under ultraviolet light of the first wavelength and/or emitting visible light of a different colour to the first luminescent region (6) when viewed under ultraviolet light of the second wavelength. A security paper (90) and a security document comprising such an inclusion (2), and a method (150) of manufacturing such an inclusion (2) are also disclosed.