Security Element Using Phosphorescent and Fluorescent Materials
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Solution Overview
Problem
Current security elements based on fluorescence are easily counterfeited due to the availability of commercially documented emission spectra of fluorescent materials, and they rely on limited materials with short emission lifetimes, making them unsuitable for advanced authentication methods, especially in digitally printed codes, and lack a secure link between pre-printed labels and product codes.
Innovation Solution
A security element utilizing the interaction between a phosphorescent pigment and a fluorescent dye, where the phosphorescent emission excites the fluorescent material, allowing for a time-dependent authentication criterion, and can be integrated into various printing methods, including inkjet printing, to create a secure and unique authentication feature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fluorescent materials are used for security elements, then authentication can be performed, but the security level remains moderate and is easily counterfeited
Solution Approach 1:
The patent combines phosphorescent pigments and fluorescent dyes in a single security element. The phosphorescent material provides long decay time emission while the fluorescent material provides short decay time emission, creating a composite security feature that is difficult to counterfeit. This composite approach resolves the contradiction by maintaining authentication capability while significantly increasing security against counterfeiting.
Solution Approach 2:
The patent utilizes different decay time parameters (long for phosphorescent, short for fluorescent) to create distinct authentication signatures. By measuring and comparing decay time characteristics, the system can reliably distinguish authentic security elements from counterfeits, thereby improving authentication security while reducing counterfeiting risk.
2Duration of action of moving object
If phosphorescent materials with long decay time are used, then time-dependent authentication becomes possible, but the particle size is too large for digital printing
Solution Approach 1:
The patent divides the security element into two separate printable components: phosphorescent pigment and fluorescent dye. Each component can be printed separately using digital printing technologies, and their combined effect produces the desired long decay time authentication feature. This segmentation resolves the contradiction by enabling digital printing while maintaining long emission duration through the phosphorescent component.
3Productivity
If pre-printed labels are used, then production efficiency is improved, but the link between label and product code is not secured
Solution Approach 1:
The patent merges the authentication feature directly into the pre-printed label by incorporating phosphorescent pigment and fluorescent dye. This creates an intrinsic security link between the label and the product code printed on it, ensuring that the code cannot be transferred to counterfeit labels. The merging of security features with the label itself resolves the contradiction by maintaining production efficiency while securing the label-code linkage.
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
This solution enhances the security of authentication by providing a harder-to-counterfeit feature that relies on the interaction of two materials, expanding the criteria for authentication beyond emission wavelength, and ensures a secure link between pre-printed labels and product codes, making it difficult for counterfeiters to replicate.
Implementation Method 1
MAT1 comprises a phosphorescent pigment, which is capable of emitting phosphorescence radiation in at least one first phosphorescence emission wavelength range upon excitation by electromagnetic radiation falling within a phosphorescence excitation wavelength range
Implementation Method 2
the second material MAT2 comprises a fluorescent dye or pigment, which is capable of emitting fluorescence radiation in at least one second fluorescence emission wavelength range upon excitation by electromagnetic radiation falling within a fluorescence excitation wavelength range
Implementation Method 3
Herein, the donor and acceptor are selected such that there is a spectral overlap between the phosphorescence emission wavelength range λ1e of the donor and the fluorescence excitation wavelength range λ2a of the acceptor. In consequence, the phosphorescence emission emitted by the donor is capable of exciting the fluorescence of the acceptor.
Data Source
Figure 1
Figure 2
Figure 2a~2c
AI summary
Security element comprising a first material MAT1 and a second material MAT2 formed in or on a substrate, in such a manner that areas occupied by MAT1 and MAT2 overlap partially or fully, the first material MAT1 comprising a phosphorescent pigment (donor), the second material MAT2 comprising a fluorescent dye or pigment (acceptor), wherein the phosphorescent pigment present in MAT1 is capable of emitting phosphorescence radiation in at least one first phosphorescence emission wavelength range λ1e upon excitation by electromagnetic radiation falling within a phosphorescence excitation wavelength range λ1 a, and the fluorescent dye or pigment present in MAT2 is capable of emitting fluorescence radiation in at least one second fluorescence emission wavelength range λ2e upon excitation by electromagnetic radiation falling within an fluorescence excitation wavelength range λ2a of the fluorescent dye or pigment, and said first phosphorescence emission wavelength range λ1e of the phosphorescent pigment present in MAT1 overlaps with the excitation wavelength range λ2a of the fluorescent dye or pigment present in MAT2, so that after irradiation of the security element with electromagnetic radiation within the phosphorescence excitation wavelength range λ1a the emission of fluorescence radiation in the emission wavelength range λ2e is observable.