Overlapping Luminescent Inks for Secure Authentication
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Solution Overview
Problem
Current authentication methods for luminescent markers are unreliable due to easily replicable emission spectra, requiring complex and expensive equipment for spectral analysis, and fail to provide a distinct visual effect under specific conditions, making them susceptible to counterfeiting.
Innovation Solution
A security element comprising two luminescent inks, one acting as a donor and the other as an acceptor, where the donor's excitation energy triggers the acceptor's emission in overlapping areas, creating a unique cascade effect that is difficult to replicate, combined with a method for authentication using tailored excitation wavelengths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If emission spectrum analysis is used for authentication, then authentication reliability is improved, but equipment complexity and cost increase
Solution Approach 1:
The patent changes the authentication parameter from analyzing emission spectra to analyzing excitation spectra. By measuring the excitation wavelengths that produce emission at a fixed observation wavelength, the system achieves reliable authentication without requiring complex spectral analysis equipment. This parameter transformation simplifies the device while maintaining or improving authentication reliability.
2Ease of manufacture
If multiple fluorescent dyes are used to simulate emission spectra, then ease of manufacture is improved, but authentication reliability deteriorates
Solution Approach 1:
Instead of analyzing what wavelengths are emitted (emission spectrum), the patent inverts the approach by analyzing what wavelengths are required to excite the marker (excitation spectrum). This inversion makes authentication more reliable because the excitation spectrum uniquely identifies the fluorescent marker composition, making it difficult for counterfeiters to replicate even if they can match emission spectra using multiple dyes.
3Measurement precision
If complex spectral analysis equipment is used, then measurement precision is improved, but ease of operation deteriorates
Solution Approach 1:
The patent replaces complex mechanical/optical spectral analysis systems with a simpler detection system that measures excitation wavelengths. Instead of using bulky equipment like Fabry-Perot interferometers or AOTF cameras, the system uses a straightforward excitation source and detector to measure which wavelengths excite the marker, achieving precise authentication with much simpler and more easily operated equipment.
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 a robust and reliable authentication method that is harder to counterfeit, utilizing a cascade effect for unique spectral signatures, allowing for simpler and more affordable authentication with handheld devices, while maintaining a distinct visual effect.
Implementation Method 1
The first luminescent dye or pigment, upon excitation by electromagnetic radiation falling within at least one excitation wavelength range λ1a of the first luminescent dye or pigment, is capable of emitting electromagnetic radiation in a first wavelength range λ1e that overlaps with at least one excitation wavelength range λ2a of the second luminescent dye or pigment DYE2 (acceptor), to thereby excite the second luminescent dye or pigment to emit electromagnetic radiation in a second wavelength range λ2e differing from the first wavelength range λ1e.
Implementation Method 2
These two dyes or pigments are selected such that said first luminescent dye or pigment DYE1 (donor), upon excitation by electromagnetic radiation falling within at least one excitation wavelength range λ1a of the first luminescent dye or pigment, is capable of emitting electromagnetic radiation in a first wavelength range λ1e that overlaps with at least one excitation wavelength range λ2a of the second luminescent dye or pigment DYE2 (acceptor), to thereby excite the second luminescent dye or pigment
Data Source
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AI summary
A security element comprising a first and a second pattern PAT1 and PAT2 formed in or on a substrate, the first pattern PAT1 being formed by a first material INK1 applied to a first region of the substrate, the second pattern PAT2 being formed by a second material INK2 applied to a second region of the substrate, said first and second regions of the substrate overlapping, wherein - a part of the first pattern PAT1 overlaps with a part of said second pattern PAT2, - the first material INK1 comprises a first luminescent dye or pigment DYE1, which upon excitation by electromagnetic radiation falling within an excitation wavelength range λ1a of the first luminescent dye or pigment DYE1 is capable of emitting electromagnetic radiation in at least one first emission wavelength range λ1e, and - the second material INK2 comprises a second luminescent dye or pigment DYE2, which upon excitation by electromagnetic radiation falling within an excitation wavelength range λ2a of the second luminescent dye or pigment DYE2 is capable of emitting electromagnetic radiation in at least one second emission wavelength range λ2e, and - said first emission wavelength range λ1e of the first luminescent dye or pigment DYE1 overlaps with the excitation wavelength range λ2a of the second luminescent dye or pigment DYE2, so that upon irradiation with electromagnetic radiation within the excitation wavelength range λ1a of the first luminescent dye or pigment DYE1 the second luminescent dye or pigment DYE2 is excited, in the area of overlap of the patterns, to emit electromagnetic radiation in the emission wavelength range λ2e.