Optical Effect Layer with Nested Loops for Sharp Security Features
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Solution Overview
Problem
Existing security features, such as 'rolling ring' effects, suffer from blurred edges and difficulty in producing high-quality, dynamic, eye-catching optical effects over extended areas on security documents, which are challenging to verify regardless of document orientation and are hard to replicate on a mass scale.
Innovation Solution
An optical effect layer (OEL) comprising nested loop-shaped areas with non-spherical magnetic or magnetizable particles, oriented to follow tangents of curved or circular paths within a magnetic field, creating a viewing-angle dependent motion effect that is sharp and easily detectable, using a magnetic field-generating device to align particles in a binder composition before hardening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If Fresnel type reflecting surfaces with oriented pigment particles are used to create rolling bar effects, then a dynamic optical effect is achieved, but the edges become blurred and the effect is difficult to verify from different orientations
Solution Approach 1:
The patent applies spherical magnets instead of flat Fresnel surfaces to orient the pigment particles. The spherical geometry creates radially oriented particles that follow curved field lines, producing sharp loop-shaped patterns with well-defined edges. This curvature-based approach resolves the blurring issue while maintaining the dynamic optical effect across different viewing angles.
Solution Approach 2:
The patent transitions from two-dimensional Fresnel reflecting surfaces to three-dimensional spherical magnets. This dimensional change allows the magnetic field to penetrate and orient particles throughout the volume of the coating layer, creating sharp, well-defined patterns that maintain their integrity from different orientations and viewing angles.
2Device complexity
If a single dipole magnet is used to orient particles in a coating layer, then the production process is simplified, but the magnetic field intensity decreases rapidly with distance making it difficult to achieve high-quality effects over extended areas
Solution Approach 1:
The patent divides the magnetic field-generating device into multiple spherical magnets arranged in an array rather than using a single dipole magnet. This segmentation allows the magnetic field to be distributed across a larger area, maintaining sufficient field intensity over extended coating areas while still using relatively simple spherical magnet components.
Solution Approach 2:
The patent combines multiple spherical magnets into a unified array configuration where their individual magnetic fields work together to create a comprehensive orientation field across the entire coating area. This merging of multiple field sources extends the effective working area while maintaining field intensity through the cumulative effect of adjacent magnets.
3Difficulty of detecting and measuring
If magnetic or magnetizable particles are oriented in a magnetic field to create security features, then the security feature becomes detectable, but it becomes easier to replicate and counterfeit
Solution Approach 1:
The patent creates security features with specific local characteristics through the loop-shaped patterns formed by oriented particles. The unique combination of loop shapes, particle orientations following spherical field lines, and nested area configurations creates a locally distinctive pattern that is easily detected but difficult to replicate without the specific spherical magnet array process.
Solution Approach 2:
The patent uses composite coating layers containing magnetic or magnetizable particles suspended in a binder material. This composite structure, when oriented by the spherical magnet array, creates a complex multi-component security feature that combines magnetic properties, optical effects, and specific geometric patterns, making it more difficult to counterfeit while remaining detectable.
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 OEL provides a clear, dynamic, and easily verifiable security feature that is difficult to counterfeit, maintaining sharpness and contrast across various orientations, enhancing document security and decorative applications with improved visual impact.
Implementation Method 1
exposing the coating composition in a first state to the magnetic field of a magnetic-field-generating device, thereby orienting at least a part of the non-spherical magnetic or magnetizable particles
Implementation Method 2
An optical effect layer (OEL) comprising a plurality of non-spherical magnetic or magnetizable particles
Implementation Method 3
hardening the coating composition to a second state so as to fix the magnetic or magnetizable non-spherical particles in their adopted positions and orientations
Implementation Method 4
The non-spherical particles have non-isotropic reflectivity, that is, they provide a viewing-angle dependent optical effect
Data Source
Figure 1A~1B
Figure 1C
Figure 2a~2c
AI summary
The invention relates to the field of the protection of security documents such as for example banknotes and identity documents against counterfeit and illegal reproduction. In particular, the invention relates to optical effect layers (OEL) showing a viewing-angle dependent optical effect, devices and processes for producing said OEL and items carrying said OEL, as well as uses of said optical effect layers as an anti-counterfeit means on documents. The OEL comprises a plurality of non-spherical magnetic or magnetizable particles, which are dispersed in a coating composition comprising a binder material, the OEL comprising two or more loop-shaped areas, being nested around a common central area that is surrounded by the innermost loop-shaped area, wherein, in each of the loop-shaped areas, at least a part of the plurality of non-spherical magnetic or magnetizable particles are oriented such that, in a cross-section perpendicular to the OEL layer and extending from the centre of the central area to the outer boundary of the outermost loop-shaped area, the longest axis of the particles in each of the cross-sectional areas of the looped-shaped areas follow a tangent of either a negatively curved or a positively curved part of hypothetical ellipses or circles.