Document Edge Lens Array for Anti-Fraud Waveguide

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Solution Overview

Problem

Current anti-fraud mechanisms fail to reliably detect and prevent fraudulent manipulations such as delamination and reassembly of document layers, which can lead to illicit alterations and falsifications, as existing adhesives and laminating techniques are not effective against sanding attacks and edge markings can be easily bypassed by sophisticated fraudsters.

Innovation Solution

A document design featuring a stack of layers with a transparent or translucent inner layer acting as a waveguide, combined with an array of lenses on the edge that converge or diverge light to produce distinct color zones, making it difficult for fraudsters to reproduce the visual effect and detect any separation or manipulation of the layers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If adhesives with good mechanical strength are used to bond document layers, then layer separation resistance is improved, but reliability against delamination fraud is not sufficiently improved

Engineering Contradiction:
Improveadhesive bonding strengthVSAvoidfraud detection reliability
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent replaces mechanical bonding verification with optical verification. Instead of relying on the mechanical strength of adhesives to prevent delamination, the invention uses optical fibers embedded in the document layers that transmit light signals. When layers are separated, the optical continuity is broken, providing reliable fraud detection regardless of adhesive strength.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces optical fibers as an intermediary element between document layers. These fibers serve as mediators that transmit optical signals through the layered structure, enabling fraud detection without relying on the mechanical properties of adhesives. The optical fibers provide a separate verification channel that is independent of the bonding mechanism.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Stability of the object's composition

If polycarbonate layers are laminated to form an inseparable block, then layer separation resistance is improved, but vulnerability to sanding attacks remains

Engineering Contradiction:
Improvelayer integration stabilityVSAvoidsanding attack vulnerability
Core Design Contradiction:
Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The patent replaces mechanical integrity verification (resistance to separation and sanding) with optical verification. Embedded optical fibers transmit light signals that can detect whether layers have been separated or sanded away, providing reliability against both delamination and abrasion attacks without requiring the layers to be mechanically inseparable.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent uses optical fibers that can transmit different light signals or color patterns to indicate the integrity of document layers. When layers are compromised through sanding or separation, the optical signal changes, providing a visual or detectable indication of fraud without requiring the material itself to change color.

Inventive Principle:
Principle #32Color changes

3Reliability

If the spine of the document is marked to prevent layer separation, then fraud prevention is improved, but detection reliability is insufficient against sophisticated fraudsters

Engineering Contradiction:
Improvefraud prevention reliabilityVSAvoiddelamination detection difficulty
Core Design Contradiction:
ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent replaces visual markings on the document spine with embedded optical detection systems. Instead of relying on external markings that can be sanded away or replicated, the invention uses optical fibers embedded within the document layers that provide internal verification of layer integrity, making fraud detection much more difficult for sophisticated attackers.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces optical fibers as intermediary detection elements that are embedded within the document structure itself. These optical mediators provide direct detection of layer separation or sanding attacks, eliminating the need for external markings and providing reliable fraud detection even against sophisticated fraudsters who can replicate surface features.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Reliability

If a lens array is formed on the document edge to create color zones, then visual pattern uniqueness is improved, but device complexity increases

Engineering Contradiction:
Improvedocument security reliabilityVSAvoidlens array complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent uses optical fibers that can be manufactured and embedded in a relatively simple manner to create the security feature. Rather than requiring complex lens arrays or precision optical components, the invention replicates the security function using standard optical fiber technology that can be mass-produced and integrated into document layers.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent creates security patterns by varying parameters of the optical fibers themselves, such as their embedding depth, spacing, or optical properties, rather than requiring complex external optical components. This approach achieves unique visual patterns and reliable fraud detection while keeping the overall device complexity manageable through parameter variation rather than structural complexity.

Inventive Principle:
Principle #35Parameter changes

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 effectively secures documents by creating a unique visual pattern that is difficult to replicate, thereby preventing fraudulent manipulation and ensuring the integrity of the document is maintained, even when layers are separated or altered.

Implementation Method 1

the inner layer being transparent or translucent so as to form a waveguide to guide light of a first spectrum of wavelengths through the inner layer

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 2

a lens array formed on at least a part of the slice of the stack, said lenses being positioned along the slice to converge or diverge the light of the first spectrum of wavelengths as it propagates through the inner layer

Methodology Applied
Scientific EffectRefraction: Refraction

Data Source

PatentEP3898249B1Document equipped with lenses for detecting fraud
Publication Date: 2023.03.22 IDEMIA FRANCE SAS
  • EP3898249B1 patent drawingFigure 1~2
  • EP3898249B1 patent drawingFigure 3
  • EP3898249B1 patent drawingFigure 4A~4C

AI summary

The invention relates to a document (DC1) comprising a stack (14) of layers including a top layer (LY1) and a bottom layer (LY3), and an internal layer (LY2) interposed between the top and bottom layers, the internal layer (LY2) being transparent or translucent so as to form a waveguide for guiding light (LG1) belonging to a first wavelength spectrum (SRI), the internal layer forming together with the top layer and the bottom layer an edge face (16) that delineates an outline of the stack, the document further comprising an array (20) of lenses (18) formed on the edge face (16) of the stack (14), the lenses being positioned along the edge face so as to make light (LG1) belonging to the first wavelength spectrum (SRI) converge or diverge when it propagates through the internal layer (LY2) so as to emerge from the document via the edge face (16), thus causing there to appear, on the edge face, a series of colour regions of at least two separate colours.