Security Element with Luminescent Microstructures

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Solution Overview

Problem

Existing security elements for valuables and documents are vulnerable to counterfeiting using office printers, such as multi-color inkjet printers, as they can replicate luminescence features easily, lacking sufficient protection against unauthorized reproduction.

Innovation Solution

A security element featuring a first color area that appears uniform and homogeneous to the naked eye, but under UV or IR excitation, reveals two distinct luminescence colors, utilizing microstructure elements and luminescent substances that produce a uniform visible color through color mixing, making it difficult to replicate with conventional office printers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If luminescent substances are used to create security features, then the authenticity can be verified under UV light, but the features can be easily replicated by office inkjet printers

Engineering Contradiction:
Improvesecurity against forgeryVSAvoiddifficulty to replicate
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The security feature is divided into multiple color regions (first color region with uniform visible color, second color region with different luminescence colors) that cannot be reproduced by standard inkjet printing. This segmentation creates a complex multi-color luminescent pattern that requires specialized equipment to manufacture, thereby improving security while maintaining feasibility for legitimate production.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the security element have different luminescence properties. The first color region displays a uniform visible color that appears homogeneous to the naked eye, while the second color region contains multiple luminescent substances that emit different colors under UV excitation. This local differentiation in luminescence characteristics creates a security feature that is difficult to replicate with conventional printing technology.

Inventive Principle:
Principle #3Local quality

2Reliability

If multiple luminescent substances with different luminescence colors are used, then the security level increases, but the manufacturing complexity increases

Engineering Contradiction:
Improvesecurity levelVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Multiple luminescent substances with different luminescence colors are combined within the second color region to create a unified security feature. These substances are integrated into the printing ink or coating layer, allowing them to be applied in a single manufacturing process step. This merging approach increases security by creating complex multi-color luminescence patterns while avoiding the need for separate manufacturing steps for each luminescent substance.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The security element uses composite materials that combine multiple luminescent substances with different emission characteristics. This composite approach allows the integration of multiple functional properties (different luminescence colors) into a single material system, thereby increasing security levels without proportionally increasing manufacturing complexity.

Inventive Principle:
Principle #40Composite materials

3Shape

If the first color region displays a uniform visible color, then the appearance is homogeneous and attractive, but the uniformity can be replicated by printers

Engineering Contradiction:
Improvevisual appearanceVSAvoidauthenticity verification
Core Design Contradiction:
ShapeVSReliability

Solution Approach 1:

The first color region is designed to display a uniform visible color under normal lighting conditions, creating an attractive and homogeneous appearance. However, under UV excitation, this region reveals its true nature through luminescence, displaying a different color or pattern that confirms authenticity. This color change behavior creates a visual mystery that is difficult to replicate with standard printing, as the uniform appearance is only maintained under specific lighting conditions.

Inventive Principle:
Principle #32Color changes

Solution Approach 2:

The visual appearance of the first color region is dynamic rather than static. It presents a uniform appearance under normal viewing conditions but transforms when exposed to UV light, revealing luminescence characteristics that confirm authenticity. This dynamic behavior creates a security feature that adapts to different viewing conditions, making it difficult for counterfeiters to replicate the authentic appearance under all lighting conditions.

Inventive Principle:
Principle #15Dynamics

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

The solution provides a high level of security against forgery by creating a visually uniform appearance that only reveals its authenticity under specific light conditions, significantly hindering counterfeiting attempts with standard office printing technology.

Implementation Method 1

The term luminescence encompasses phosphorescence and fluorescence, whereby luminescence can be excited by invisible UV or IR radiation.

Methodology Applied
Scientific EffectLuminescence: Luminescence

Implementation Method 2

The term luminescence encompasses phosphorescence and fluorescence

Methodology Applied
Scientific EffectFluorescence: Fluorescence

Implementation Method 3

The term luminescence encompasses phosphorescence and fluorescence

Methodology Applied
Scientific EffectPhosphorescence: Phosphorescence

Implementation Method 4

The microstructure elements have two or more different colors, which, from a normal viewing distance, create the perceived color impression for the observer through color mixing, in particular subtractive color mixing.

Methodology Applied
Scientific EffectColor mixing:

Data Source

PatentEP4049852B1Security element, data carrier and manufacturing method
Publication Date: 2024.01.31 GIESECKE & DEVRIENT CURRENCY TECHNOLOGY GMBH
  • EP4049852B1 patent drawingFigure 1~2(b)
  • EP4049852B1 patent drawingFigure 3(a)~5
  • EP4049852B1 patent drawingFigure 6~7(c)

AI summary

The invention relates to a security element (20) for securing valuables. The security element has a feature area (22) comprising a first color area (22) formed from visually visible printing inks, and a second color area (30, 32) formed from luminescent substances that are not visible without excitation and which at least partially overlaps the feature area (22). When viewed with the naked eye in visible light, the first color area (22) of the feature area exhibits a homogeneous appearance with a uniform visible color at least in certain areas, and when viewed under UV or IR excitation light, it displays at least two different luminescent colors.The first color area (22) contains a microstructure arrangement of differently colored microstructure elements (24, 26) that have a characteristic dimension below the resolution limit of the human eye and each exhibit one of at least two different colors, producing a uniform color visible to the naked eye, at least in some areas, through color mixing. The invention also includes a data carrier with such a security element and a method for manufacturing such a security element.