Value Document Authenticity via Luminescence Intensity Ratios

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Solution Overview

Problem

Current methods for determining the authenticity of value documents rely heavily on spectral and temporal analysis of luminescence, which can be complex and require multiple sensors, whereas there is a need for a more straightforward and efficient approach to authenticate documents using luminescent areas.

Innovation Solution

A method involving a value document with two luminescent areas that are illuminated using different temporal structures of light, allowing for the measurement of time-averaged luminescence intensities to determine authenticity, where a single sensor can measure and compare these intensities to provide authentication information.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If spectral and temporal analysis of luminescence is used to determine authenticity, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improveauthenticity determination accuracyVSAvoidauthentication system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts only the intensity measurement aspect from the full spectral and temporal analysis, discarding the complex spectral decomposition while retaining sufficient authentication capability through intensity ratios measured under different illumination conditions

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces expensive, complex spectral analysis systems with simpler, more affordable intensity measurement devices that provide adequate authentication functionality for the intended application

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Measurement precision

If multiple sensors are used for spectral and temporal analysis, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improveluminescence characterization accuracyVSAvoidsensor system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent makes a single sensor perform multiple measurement functions by sequentially illuminating the luminescent area with different temporal structures and analyzing the time-averaged intensity responses, eliminating the need for multiple specialized sensors

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent combines spectral information from different luminescent materials into a single intensity measurement channel, merging what would traditionally require multiple sensors into one unified measurement approach

Inventive Principle:
Principle #5Merging (Combining)

3Illumination intensity

If fluorescent printing inks are used for visual checks, then luminescence intensity is improved, but separation from background becomes difficult

Engineering Contradiction:
Improveluminescence intensityVSAvoidfluorescent background interference
Core Design Contradiction:
Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

The patent uses periodic modulation of the excitation light with specific temporal structures, allowing phosphorescent signals to be distinguished from fluorescent background through their different temporal response characteristics during the illumination cycles

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent applies a pre-illumination step that allows phosphorescent materials to build up energy storage before the actual measurement, creating a time delay that separates the phosphorescent signal from the immediate fluorescent response

Inventive Principle:
Principle #10Preliminary action

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 method simplifies the authentication process by using intensity measurements alone, allowing for the authentication of value documents with combined fluorescent and phosphorescent prints using a single sensor, enhancing efficiency and reducing complexity.

Implementation Method 1

A step of the method comprises providing a value document having a first luminescent area and a second luminescent area. Another step includes illuminating the first luminescent area using a first illumination. Another step comprises upon illuminating the first luminescent area using the first illumination, measuring a first luminescence intensity that is emitted by the first luminescent area.

Methodology Applied
Scientific EffectLuminescence: Luminescence

Implementation Method 2

For visual checks, fluorescent printing inks may be preferred because they allow high luminescence intensity and fine printing details.

Methodology Applied
Scientific EffectFluorescence: Fluorescence

Implementation Method 3

For optoelectronic measurements, phosphorescent printing inks may be preferred because their emission can easily be separated from a fluorescent background

Methodology Applied
Scientific EffectPhosphorescence: Phosphorescence

Data Source

PatentEP4411679A1Method of determining an authenticity of a value document, method of manufacturing a value document and set of value documents
Publication Date: 2024.08.07 GIESECKE & DEVRIENT CURRENCY TECHNOLOGY GMBH
  • EP4411679A1 patent drawingFigure 1~5
  • EP4411679A1 patent drawingFigure 6~7
  • EP4411679A1 patent drawingFigure 8~9

AI summary

The invention relates to a method of determining an authenticity of a value document (1). In step (S1) of the method a value document (1) having a first luminescent area (11) and a second luminescent area (12) is provided. In step (S2) the first luminescent area (11) is illuminated using a first illumination (21), and in step (S3), upon illuminating the first luminescent area (11) using the first illumination (21), a first luminescence intensity (31) emitted by the first luminescent area is measured. In step (S4), the second luminescent area (12) is illuminated using the first illumination (21), and in step (S5), upon illuminating the second luminescent area (12) using the first illumination (21), a second luminescence intensity (32) emitted by the second luminescent area (12) is measured. In step (S6), an authenticity information is obtained based on the measured first and second luminescence intensities (31, 32).