Multi-layer Security Element Mask Registration

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Solution Overview

Problem

Existing multi-layer bodies used for security elements, such as banknotes and identity documents, face challenges in achieving seamless transitions between layers due to production tolerances, which compromises security against forgery and visual appearance.

Innovation Solution

A method where the second layer or layer system is used as a mask to structure the first layer or layer system, ensuring precise registration by extending into areas covered and not covered by the first layer, using etching resists and protective lacquers that also provide decorative effects, and employing photoresists for selective removal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If sequential application of individual layers is used to produce multi-layer bodies, then the production process is simple and flexible, but the layers cannot be arranged in precise register with one another due to production tolerances

Engineering Contradiction:
Improveproduction process simplicityVSAvoidlayer registration accuracy
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The method applies a preliminary action by extending the second layer beyond the boundaries of the first layer before structuring. This overextension creates a mask that defines the exact registration boundaries for subsequent etching of the first layer, ensuring precise alignment without requiring high precision in the layer application step itself.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The second layer serves as an intermediary element - it is applied first and extends beyond the first layer to act as a masking boundary. This intermediary layer mediates the registration problem by providing physical boundaries that guide the structuring of the first layer, transforming a precision positioning problem into a boundary-defined patterning problem.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If sequential construction of multi-layer bodies is used, then individual layers can be produced with standard methods, but seamless transitions between layers cannot be reliably achieved

Engineering Contradiction:
Improveproduction efficiencyVSAvoidseamless transition reliability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The second layer is applied in advance with intentional overextension beyond the first layer boundaries. This preliminary overextension creates a built-in mask that ensures seamless transitions by defining exact etching boundaries, making the seamless transition reliable without requiring post-production alignment adjustments.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The second layer serves a dual function: it is both a visible feature layer and a self-generated mask for structuring the first layer. The layer itself provides the boundaries for its own precise positioning relative to the first layer, eliminating the need for external alignment mechanisms or post-production registration adjustments.

Inventive Principle:
Principle #25Self-service

3Manufacturing precision

If layers are arranged in precise register, then security against forgery and visual appearance are improved, but the production process becomes more complex

Engineering Contradiction:
Improvelayer registration accuracyVSAvoidproduction process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

Instead of attempting to achieve precise registration during layer application, the method performs a preliminary action of extending the second layer beyond boundaries. This simple overextension creates self-defined boundaries that guide subsequent structuring, achieving high precision without complex positioning equipment or procedures.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The extended second layer acts as an intermediary mask that simplifies the structuring process. Rather than requiring precise positioning of the first layer relative to the second, the extended second layer provides physical boundaries that define where etching should occur, converting a complex alignment problem into a simple boundary-following process.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

This method enables the production of multi-layer bodies with improved security against forgery and enhanced visual appeal by ensuring seamless transitions between layers, making them difficult to reproduce and highly secure.

Implementation Method 1

The partial second layer or the partial second layer system is an etching resist or comprises an etching resist

Methodology Applied
Scientific EffectEtching resist:

Implementation Method 2

The partial first layer or the partial first layer system is structured in step c) by etching

Methodology Applied
Scientific EffectPhotoresist: Photopolymerisation

Data Source

PatentEP3074239B2Multi-layer body as security element and method for the production thereof
Publication Date: 2022.04.13 LEONHARD KURZ STIFTUNG & CO KG
  • EP3074239B2 patent drawingFigure 1(A)~2(C)
  • EP3074239B2 patent drawingFigure 3~4
  • EP3074239B2 patent drawingFigure 5~6

AI summary

The invention relates to a method for producing a multi-layer body, in particular a security element, wherein a partial first layer or a partial first layer system is created on a substrate, said partial first layer or partial first layer system being provided in a first portion and not in a second portion. Subsequently, a partial second layer or a partial second layer system is created, said partial second layer or partial second layer system being provided in a third portion and not in a fourth portion, which third portion overlaps with the first and second portions. The partial first layer or the partial first layer system is then formed as a mask structure using the partial second layer or the partial second layer system.