Magnetic Security Element Testing via Dual-Step Magnetization

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Solution Overview

Problem

Existing methods for checking value documents with magnetic coding struggle to reliably distinguish between high-coercivity, low-coercivity, and combined magnetic areas due to signal overlap, making it difficult to differentiate these areas effectively.

Innovation Solution

The method involves a security element with high-coercive, low-coercive, and combined magnetic areas, where the combined areas contain both materials with the same remanent flux density, and a two-step magnetization process using magnetic fields of different strengths to align and detect the areas, allowing for distinct signal analysis to identify each type of area.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If combined magnetic areas containing both high-coercivity and low-coercivity magnetic materials are used in security elements, then the magnetic coding capacity is improved, but the magnetic signals of differently coercive materials overlap making the areas difficult to distinguish

Engineering Contradiction:
Improvemagnetic coding capacityVSAvoiddistinguishability of magnetic areas
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent segments the detection process into two distinct stages: first detecting the combined magnetic areas (containing both high-coercivity and low-coercivity materials) using a magnetic field strength that magnetizes both materials, then detecting the remaining high-coercivity magnetic areas using a stronger magnetic field. This temporal and field-strength-based segmentation allows the system to distinguish between different magnetic area types despite their signal overlap when detected simultaneously.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs dynamic adjustment of magnetic field strength during the detection process. The system first applies a weaker magnetic field to detect combined magnetic areas, then increases the field strength to detect high-coercivity areas. This dynamic field strength adjustment enables the detection system to selectively target different magnetic material types at different stages, resolving the distinguishability problem.

Inventive Principle:
Principle #15Dynamics

2Device complexity

If a single magnetic field strength is used for detection, then the detection process is simplified, but combined magnetic areas produce reduced signals that lie between high-coercivity and low-coercivity signals making differentiation impossible

Engineering Contradiction:
Improvedetection process complexityVSAvoidsignal differentiation capability
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent implements periodic detection actions with two distinct phases: first, a detection phase using a weaker magnetic field to identify combined magnetic areas; second, a detection phase using a stronger magnetic field to identify high-coercivity magnetic areas. This periodic alternation between different field strengths creates distinct signal patterns for different magnetic area types, enabling precise differentiation despite the initial signal overlap.

Inventive Principle:
Principle #19Periodic 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 approach enables reliable differentiation of high-coercivity, low-coercivity, and combined magnetic areas by analyzing the magnetic signals produced after the magnetization steps, improving the accuracy of document authentication.

Implementation Method 1

The security element is magnetized by a first magnetic field with a first magnetic field strength, the direction of which runs in a first direction, which aligns the magnetization of the high-coercivity and low-coercivity magnetic materials in a first direction

Methodology Applied
Scientific EffectMagnetic field alignment: Magnetic Field

Implementation Method 2

The security element is magnetized by a second magnetic field with a second magnetic field strength, the direction of which runs in a second direction which is antiparallel to the first direction

Methodology Applied
Scientific EffectAntiparallel magnetization: Magnetic Field

Implementation Method 3

The remaining magnetization is checked by means of an inductive magnetic head

Methodology Applied
Scientific EffectInductive magnetic detection: Electromagnetic Induction

Data Source

PatentEP2473978B1Method and device for testing value documents
Publication Date: 2017.07.05 GIESECKE & DEVRIENT CURRENCY TECHNOLOGY GMBH
  • EP2473978B1 patent drawingFigure 1~2
  • EP2473978B1 patent drawingFigure 3~4
  • EP2473978B1 patent drawingFigure 5~6

AI summary

The invention relates to a method and a device for testing value documents comprising a security element having a plurality of magnetic fields, including at least one high coercivity magnetic field, at least one low coercivity magnetic field, and at least one combined magnet field comprising both the high coercivity and the low coercivity magnetic material. After magnetizing all magnetic fields in a first direction, first magnetic signals of the security element are detected using a first magnetic detector. After a subsequent second magnetization, performed antiparallel to the first magnetization, second magnetic signals of the security element are detected. The second magnetic signals or a signal derived therefrom are compared to two thresholds for identifying the magnetic fields.