Phosphor Substrate Authentication for Wear-Resistant Value Documents
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Solution Overview
Problem
Existing value document authentication systems face challenges in accurately distinguishing authentic documents from counterfeits due to unpredictable deterioration of covert features, leading to incorrect identification, especially when these features are contained within the printed ink and subjected to wear and attrition.
Innovation Solution
A value document authentication apparatus utilizing a phosphor exciting light source, sensors to detect infrared radiation, and processing units to normalize and compare intensity data from pre-selected regions, enhancing security by incorporating phosphors with distinct infrared wavelengths and emission decay times, and accounting for wear and pattern interactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If covert features are incorporated in the printed ink on the substrate, then authentication security is improved, but the features are subjected to wear and attrition causing unpredictable deterioration of emission spectra
Solution Approach 1:
The patent extracts the phosphor material from the printed ink layer and incorporates it directly into the substrate material itself. This separation removes the phosphor from the wear-prone printed surface while maintaining its authentication function within the more stable substrate structure.
Solution Approach 2:
The phosphor is pre-incorporated into the substrate during substrate formation rather than being applied later through printing. This preliminary integration ensures the phosphor is protected from wear before the document even enters circulation.
2Reliability
If normalized intensity data is used for authentication, then the likelihood of misidentifying authentic documents is reduced, but the device complexity increases due to normalization and comparison processing
Solution Approach 1:
The system performs preliminary normalization of intensity data during the authentication process, establishing baseline characteristics of genuine documents before comparing test documents against these normalized standards. This upfront processing simplifies subsequent comparison operations.
Solution Approach 2:
The patent introduces normalized intensity data as an intermediary representation between the raw sensor measurements and the final authentication decision. This intermediate form facilitates more reliable comparisons while managing complexity through standardized data processing.
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 provides a more secure authentication method by normalizing intensity data across multiple orientations and accounting for wear, reducing the likelihood of misidentifying authentic documents as counterfeits and enhancing the security of value documents.
Implementation Method 1
the value document includes a uniform distribution of at least one phosphor capable of emitting infrared radiation with at least one distinct infrared wavelength and the phosphor exciting light source has sufficient energy to excite emission from the phosphor
Implementation Method 2
at least one sensor arranged to detect, with spectral resolution, infrared radiation emitted from the value document within a pre-selected track excited by the phosphor exciting light source
Data Source
Figure 1
Figure 2a~2b
Figure 3a~3b
AI summary
A value document authentication apparatus and system that includes value document substrates having a uniform distribution of one or more phosphors that emit infrared radiation in one or more wavelengths, which can be measured at the same location on the value document that is illuminated by a phosphor exciting light source when the document passes the light source with a uniform velocity. The illumination and measurement locations on the value document can be offset. The measured infrared radiation as a series of overlapped measurements along a pre-selected track in the value document represents an intensity profile, which can be normalized after removing high variations. The normalized intensity profile of a test value document can be compared with normalized intensity profile from valid reference documents to authenticate the test value document.