Cascading Phosphors for Secure Article Authentication
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for authenticating articles using luminescent features are vulnerable to reverse engineering by sophisticated counterfeiters, as the properties of well-known phosphors can be detected and replicated, and there is a need for difficult-to-detect phosphors suitable for incorporation into articles like paper and textiles.
Innovation Solution
The use of cascading phosphors with at least three rare earth active ions in a host material, where energy transfer between ions produces luminescent emissions at specific wavelengths, making it difficult to mimic the spectral and temporal characteristics, and a smart detector is used to authenticate articles based on pre-selected detection parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional luminescent pigments are used for authentication, then the authentication method is simple and detectable, but the security is vulnerable to reverse engineering by counterfeiters
Solution Approach 1:
The patent changes the spectral parameters of the luminescent material by using a phosphor that emits in the short-wave infrared region (1000-2500 nm) rather than visible wavelengths. This parameter change in emission wavelength makes the authentication feature undetectable by conventional visual inspection and standard spectroscopic equipment, thereby improving security while maintaining detection capability through specialized sensors.
Solution Approach 2:
The patent employs a composite phosphor material containing multiple rare earth elements (at least three different rare earths) doped into a host matrix. This composite structure creates complex spectral characteristics with multiple emission lines and decay times that are difficult to replicate, enhancing authentication security while the material remains detectable through appropriate infrared sensors.
2Reliability
If multiple rare earth ions are used in cascading configuration, then the spectral complexity increases making reverse engineering difficult, but the device complexity and detection requirements increase
Solution Approach 1:
The patent utilizes the natural periodic decay characteristics of multiple rare earth ions after excitation. Each rare earth element has distinct decay times, creating a temporal signature that is periodic in nature. The detection system measures the decay curve over time, and the complexity of distinguishing multiple exponentials provides the security feature without requiring complex real-time modulation or modulation of the excitation source.
Solution Approach 2:
The host material acts as an intermediary matrix that accommodates multiple rare earth ions and facilitates energy transfer between them. This intermediary structure enables the cascading energy transfer mechanism where one rare earth ion transfers energy to another, creating complex spectral features while the host material itself remains relatively simple and easy to manufacture.
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 the security of articles by making it difficult for counterfeiters to reverse-engineer the phosphors, providing a complex spectral space for authentication, and increasing the intelligence of the detection system to rely on specific emission parameters rather than mere presence, thus improving the resilience against forgery.
Implementation Method 1
the first active ion transfers energy nonradiatively to the second active ion and the second active ion transfers energy nonradiatively to the third active ion
Implementation Method 2
at least one of the active ions produces a luminescent emission having a wavelength of at least about 1700 nm
Data Source
AI summary
Cascading phosphors are described herein that produce emissions when they are excited by incident radiation. The cascading phosphors can be applied to articles, and can be useful in authenticating the article. The cascading phosphors include a host and at least three active ions.