Luminescent Material Authenticity Detection via Zero Crossing
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Solution Overview
Problem
Existing methods for determining the authenticity of objects using fluorescent materials require highly accurate and complex measurement systems, making them economically unfeasible for high-throughput applications such as banknote processing.
Innovation Solution
A procedure that uses at least two different fluorescent materials with distinct cooldown behaviors, allowing for the detection of zero crossings or identity signals through a difference formation of signals, which can be detected using simpler measuring systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If highly accurate measurement systems are used to precisely characterize the decay behavior of phosphors, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent divides the measurement approach into two distinct parts: using two different phosphors with different decay behaviors instead of one complex measurement system. This segmentation allows simpler detectors to be used while maintaining high measurement precision through the differential decay characteristics
Solution Approach 2:
The patent changes the measurement parameter from directly measuring absolute decay curves (which requires high-precision complex systems) to measuring the difference or ratio of decay behaviors between two phosphors. This parameter transformation enables the use of simpler measurement systems while achieving the same level of authenticity verification
2Measurement precision
If highly accurate measurement systems are used to characterize decay behavior, then measurement precision is improved, but manufacturing cost increases
Solution Approach 1:
The patent segments the measurement function into two simpler components (two different phosphors with different decay behaviors) rather than requiring one complex high-precision measurement system. This reduces manufacturing costs while maintaining measurement precision
Solution Approach 2:
The patent uses phosphors with short decay times (ns range) that can be measured quickly and discarded or reset, replacing the need for expensive, complex, and delicate high-precision measurement equipment. The simple detectors used are more robust and cheaper to manufacture
3Productivity
If measurement time is reduced for high throughput applications, then productivity is improved, but measurement precision deteriorates
Solution Approach 1:
The patent uses periodic excitation with light pulses to repeatedly excite the phosphors and measure their decay behaviors. By using phosphors with short decay times in the ns range and applying periodic excitation, the system can perform rapid sequential measurements that maintain statistical precision while achieving high throughput suitable for banknote processing speeds
Solution Approach 2:
The patent changes the temporal parameter by using phosphors with extremely short decay times (nanosecond range) and measuring them with high-frequency periodic excitation. This allows the measurement to be completed in a fraction of the time required by previous methods, enabling high productivity while maintaining precision through the use of simple, fast measurements
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 approach enables an efficient and cost-effective authenticity check by reducing the complexity of measurement systems and allowing for high-frequency signal detection, making it suitable for high-throughput applications.
Implementation Method 1
marking the object with a first phosphor having a first temporal decay behavior, marking the object with a second phosphor having a second decay behavior that differs from the first decay behavior, exciting the phosphors with a light pulse
Data Source
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AI summary
The invention relates to a method for determining the authenticity of an object (500, 600, 700, 800), comprising the following method steps: marking the object (500, 600, 700, 800) with a first luminescent material (L1) having a first time-based decay behaviour; marking the object (500, 600, 700, 800) with a second luminescent material (L2) having a second decay behaviour which differs from the first decay behaviour; exciting the luminescent materials (L1, L2) with a light pulse; measuring the afterglow intensities (I(λ1,t), I(λ2, t)) of the two luminescent materials (L1, L2) after excitation with the light pulse. According to the invention, a differential signal (Δ(I(λ1,t), I(λ2,t)) or identity signal is formed from the afterglow intensities (I(λ1,t), I(λ2, t)) measured over the elapsed time (t), and the time (tΔ0 (I(λ1,t), I(λ2, t))) of a zero crossing of the differential signal (Δ(I(λ1,t), I(λ2,t)) or of an identity signal of a comparator is determined, and subsequently the time (tΔ0) determined by the zero crossing/the identity signal is compared with a target value.