Security Element Manufacturing Process for Banknotes

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Solution Overview

Problem

Conventional methods for creating see-through security elements in value documents, such as banknotes, result in a greasy and sticky appearance and irregular translucent zones due to the use of transparentizing compositions, which affect the aesthetics and authenticity verification.

Innovation Solution

A method involving a substrate with a waterproofing product applied around a translucent zone to prevent impregnation and migration of a transparentizing product, using iridescent or variable optical effect inks to create contrasting patterns observable from both sides, ensuring a clear and aesthetic appearance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a transparentizing composition is applied to the substrate to create a translucent zone, then the substrate becomes translucent allowing see-through effect, but the substrate develops a greasy and sticky appearance that harms aesthetics

Engineering Contradiction:
ImprovetranslucencyVSAvoidgreasy and sticky appearance
Core Design Contradiction:
Stability of the object's compositionVSObject-generated harmful factors

Solution Approach 1:

The substrate surface is divided into two distinct zones: a first zone treated with waterproofing product and a second zone treated with transparentizing composition. This segmentation allows the transparentizing composition to be applied only where translucency is desired, preventing it from spreading to areas where it would create unwanted greasy appearance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different zones of the substrate are given different properties: the first zone receives waterproofing treatment to resist composition migration, while the second zone receives transparentizing treatment to achieve translucency. This local differentiation ensures that each zone has the specific quality needed for its function.

Inventive Principle:
Principle #3Local quality

2Stability of the object's composition

If a transparentizing composition is applied to create a translucent zone, then the see-through effect is achieved, but the composition migrates to the surface creating deformed and irregular appearance with undesirable stains

Engineering Contradiction:
ImprovetranslucencyVSAvoidregularity of translucent zone
Core Design Contradiction:
Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The waterproofing product is applied to the substrate before applying the transparentizing composition. This preliminary action creates a protective barrier that prevents the transparentizing composition from migrating to the surface, ensuring that the translucent zone maintains its intended shape and regularity without deformation or staining.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The waterproofing product acts as an intermediary layer between the substrate and the transparentizing composition. It mediates the interaction by allowing the composition to impregnate the substrate for translucency while simultaneously preventing surface migration that would cause irregular appearance.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Object-generated harmful factors

If a waterproofing product is applied around the translucent zone to prevent migration, then the translucent zone maintains clear boundaries and aesthetic appearance, but the process complexity increases with multiple steps

Engineering Contradiction:
Improvemigration and irregular appearanceVSAvoidnumber of process steps
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The application of waterproofing product and transparentizing composition is merged into a single integrated process where the waterproofing layer serves dual purposes: preventing migration and defining the boundary of the translucent zone. This combination reduces the need for separate complex processing steps.

Inventive Principle:
Principle #5Merging (Combining)

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 method produces a secure and aesthetically pleasing see-through effect with clear pattern visibility from both sides, reducing the diffuse aspect and maintaining document authenticity without the greasy appearance, enhancing the security features of value documents.

Implementation Method 1

the waterproofing product preventing the impregnation of the substrate by the transparentizing product in the first peripheral zone

Methodology Applied
Scientific EffectHydrophobe: Hydrophobe

Implementation Method 2

applying the transparentizing product to at least the second zone so as to impregnate the substrate to make it translucent in this zone

Methodology Applied
Scientific EffectAbsorption (physical): Absorption (physical)

Implementation Method 3

the transparentizing product has a tendency to migrate to the surface of the substrate

Methodology Applied
Scientific EffectDiffusion: Diffusion

Implementation Method 4

the waterproofing product being an ink chosen from an iridescent ink, an ink with a variable optical effect

Methodology Applied
Scientific EffectIridescence: Iridescence

Data Source

PatentEP2429825B1Manufacturing process of a security element for a security document
Publication Date: 2014.02.12 OBERTHUR FIDUCIAIRE SAS
  • EP2429825B1 patent drawingFigure 1A~2B
  • EP2429825B1 patent drawingFigure 3~4B
  • EP2429825B1 patent drawingFigure 5A~6D

AI summary

A translucent area (Z2) is formed in the element (14) by applying a substance (24) that transparentizes its substrate (12). Thus, the method includes a step of applying a substance (20) that impermeabilizes the substrate (12) over a first area (Z1) on a first side (F1) of the substrate, surrounding a second area (Z2) devoid of the impermeabilizing substance (20). The impermeabilizing substance (20) prevents impregnation of the substrate (12) by the transparentizing substance (24) in the first area (Z1). The method then includes a step of applying the transparentizing substance (24) to at least the second area (Z2) so as to impregnate the substrate (12) in order to make it translucent in this area (Z2). The first (Z1) and second (Z2) areas form first (18) and second (22) patterns respectively, making up an image that can be observed from both sides (F1, F2) of the substrate (12).