Bichromal Microspheres for Irreversible Magnetic Security Patterns

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Solution Overview

Problem

Current security documents lack effective means to irreversibly orient magnetic particles for anti-counterfeiting measures, as existing methods are either inefficient or damage-sensitive.

Innovation Solution

Incorporation of multichromal microspheres, specifically bichromal microspheres with a core and a partial magnetic coating, into ink compositions that can be oriented by a magnetic field, allowing for the creation of irreversibly magnetically induced images or patterns using conventional printing processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional magnetic pigments are used in security documents, then magnetic orientation can be achieved, but the orientation is reversible and can be easily altered by external magnetic fields

Engineering Contradiction:

Improveirreversibility of magnetic orientationVSAvoidcomplexity of magnetic particle structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies composite materials by creating multichromal microspheres that combine magnetic materials with non-magnetic colored materials in a single particle structure. This composite approach enables the particles to exhibit both magnetic responsiveness and irreversible orientation properties, resolving the contradiction between reliability and structural complexity.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent segments the magnetic particle into distinct functional zones: a magnetic material portion and a non-magnetic colored material portion. This segmentation allows each component to perform its specific function independently while working together to achieve irreversible magnetic orientation, addressing the reliability challenge without excessive complexity.

Inventive Principle:

Principle #1Segmentation

2Productivity

If optically variable magnetic pigments are used, then security features are enhanced, but the particles are difficult to orient quickly and efficiently

Engineering Contradiction:

Improvespeed of particle orientationVSAvoidsecurity feature effectiveness

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies local quality by giving different portions of the microsphere different properties: the magnetic material portion responds to magnetic fields for rapid orientation, while the non-magnetic colored material portion provides the security feature's visual characteristics. This local differentiation enables fast orientation without compromising security effectiveness.

Inventive Principle:

Principle #3Local quality

3Manufacturing precision

If multichromal microspheres with core and partial coating are used, then high-resolution irreversible images are formed, but the manufacturing process becomes more complex

Engineering Contradiction:

Improveresolution of magnetic imageVSAvoidsimplicity of ink composition preparation

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent applies preliminary action by pre-forming the multichromal microspheres with their core and partial coating structure before incorporation into the ink composition. This preliminary preparation of the complex particle structure allows the final ink formulation and application process to remain relatively simple, resolving the contradiction between manufacturing precision and ease of manufacture.

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

Enables the formation of high-resolution, irreversible magnetic images or patterns that are difficult to counterfeit, providing enhanced security against reproduction and maintaining their orientation after curing, thus enhancing the security features of documents.

Implementation Method 1

bichromal microspheres that are orientable upon application of a magnetic field

Methodology Applied

Scientific EffectMagnetic field orientation: Magnetism

Data Source

PatentEP2916968B1Irreversibly magnetically induced images or patterns

Publication Date: 2018.10.03 SICPA HOLDING SA

Figure 1A~1B
Figure 2

AI summary

The present invention relates to the field of the protection of security documents, especially banknotes, against illegal actions such as robbery or theft. In particular, the present invention relates to the field of ink compositions for producing irreversibly magnetically induced images or patterns, said inks comprising multichromal microspheres, preferably bichromal microspheres (1) that are orientable upon application of a magnetic field and that comprise at least a first portion (2) comprising one or more dyes and/or pigments and at least a second portion (3) comprising one or more magnetic or magnetizable materials, wherein said microspheres (1) comprise as the first portion a core (2) having a surface and comprising the one or more dyes and/or pigments and as the second portion a partial coating (3) covering at least a portion of the surface of said core (2) and comprising the one or more magnetic or magnetizable materials.