Diamagnetic Security Pigment for Banknote Optical Effects

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Solution Overview

Problem

Current banknotes rely on magnetizable color-shifting interference pigments for security features, which limit the variety of illusive optical effects, necessitating the development of alternative magnetic materials to enhance counterfeiting protection.

Innovation Solution

A flake structure comprising a layer of diamagnetic material, such as bismuth, combined with additional layers like reflector, dielectric, and absorber layers, dispersed in a liquid medium and applied to a substrate, where a magnetic field aligns the flakes perpendicular to its plane, creating unique optical effects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If magnetizable color-shifting interference pigments are used for security features, then security protection is provided, but the variety of illusive optical effects is limited

Engineering Contradiction:

Improvevariety of optical effectsVSAvoidsecurity protection

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent changes the magnetic property parameter of the pigment from ferromagnetic to diamagnetic, which fundamentally alters the optical effects while maintaining security functionality. This parameter change enables new illusive effects that differ from conventional magnetizable pigments, directly resolving the contradiction between security reliability and optical effect variety

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs composite flake structures containing diamagnetic materials combined with other materials to create color-shifting interference effects. These composite structures provide both the required security protection and generate diverse illusive optical effects through interference patterns, addressing both aspects of the contradiction simultaneously

Inventive Principle:

Principle #40Composite materials

2Ease of operation

If magnetizable platelets are aligned along magnetic field lines, then organization and optical effects are achieved, but the alignment direction is constrained to parallel orientation

Engineering Contradiction:

Improveplatelet alignmentVSAvoidalignment orientation

Core Design Contradiction:

Ease of operationVSAdaptability or versatility

Solution Approach 1:

The patent inverts the conventional alignment behavior by using diamagnetic materials that align perpendicular to magnetic field lines rather than parallel. This inverted response to magnetic fields provides a new degree of freedom in controlling platelet orientation, enabling versatile alignment patterns including perpendicular, radial, and tangential orientations that were not achievable with traditional ferromagnetic pigments

Inventive Principle:

Principle #13The other way round (Inversion)

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 use of diamagnetic flakes with aligned perpendicular planes generates distinct optical effects, enhancing the security features of banknotes by providing different illusive effects and improving protection against counterfeiting.

Implementation Method 1

A flake structure comprising a layer of diamagnetic material, such as bismuth

Methodology Applied

Scientific EffectDiamagnetism: Diamagnetism

Data Source

PatentUS20250092263A1Security pigment

Publication Date: 2025.03.20 VIAVI SOLUTIONS INC(US)

AI summary

A flake including a layer of a diamagnetic material; and at least one additional layer is disclosed. The flake, such as a plurality of flakes, can be dispersed in a liquid medium to form a composition. The composition can be applied to a surface of a substrate to form a security device. A method of making the security device is also disclosed.