Additive Relief Structures for Optically Variable Elements

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Solution Overview

Problem

Current methods for producing optically variable elements are not cost-effective and lack flexibility, particularly when producing small quantities or novel designs, as they often rely on traditional embossing techniques that do not allow for efficient creation on target substrates.

Innovation Solution

An additive method is employed to create relief structures with selectively modified relief elements, using techniques like inkjet printing, stereolithography, or selective laser sintering, allowing for the production of optically variable elements with varying relief shapes and sizes that change appearance based on viewing angle, enabling flexible and cost-effective production.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If traditional embossing techniques are used to produce relief structures, then manufacturing precision and reliability are improved, but manufacturing flexibility and cost-effectiveness for small quantities deteriorate

Engineering Contradiction:
Improverelief structure precisionVSAvoidproduction flexibility
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The patent replaces traditional mechanical embossing systems with additive manufacturing methods (inkjet printing, stereolithography, selective laser sintering) to create relief structures. This substitution enables digital control over relief element geometry and positioning, providing manufacturing precision while simultaneously achieving production flexibility for small quantities and novel designs without requiring physical mold changes.

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

Solution Approach 2:

The patent utilizes parameter changes in additive manufacturing processes to control the relief structure characteristics. By adjusting printing parameters, laser power, layer thickness, and material properties, the system achieves precise relief element formation with varying heights and orientations, maintaining manufacturing precision while enabling rapid adaptation to different design requirements.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If traditional embossing techniques are used, then production efficiency for large quantities is improved, but cost-effectiveness for small quantities and novel designs deteriorates

Engineering Contradiction:
Improveproduction efficiencyVSAvoidcost-effectiveness
Core Design Contradiction:
ProductivityVSEase of manufacture

Solution Approach 1:

The patent employs disposable or easily replaceable digital templates and support structures in additive manufacturing. Instead of investing in expensive, long-lived embossing molds, the system uses digital models that can be rapidly modified and printed, making the manufacturing process cost-effective for small quantities and novel designs while maintaining adequate production efficiency.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

By replacing mechanical embossing with additive manufacturing, the patent eliminates mold fabrication costs and setup time. The digital nature of the process allows rapid production of small quantities without the minimum order requirements of traditional methods, achieving cost-effectiveness while maintaining reasonable production efficiency through automated printing processes.

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

3Adaptability or versatility

If additive methods are used to create relief structures, then production flexibility and cost-effectiveness for small quantities are improved, but manufacturing precision may deteriorate

Engineering Contradiction:
Improveproduction flexibilityVSAvoidrelief structure precision
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent replaces mechanical embossing with additive manufacturing methods that use digital models and precise material deposition or selective curing. This substitution enables exact replication of digital geometry with high precision, as the relief structures are built layer-by-layer according to computer-aided design data, ensuring manufacturing precision while achieving production flexibility.

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

Solution Approach 2:

The patent controls relief structure precision through parameter optimization in additive manufacturing, including layer thickness, printing resolution, laser power, and material properties. By carefully adjusting these parameters, the system achieves high manufacturing precision comparable to traditional embossing while maintaining the flexibility of digital manufacturing.

Inventive Principle:
Principle #35Parameter changes

4Adaptability or versatility

If relief structures are created with multiple sub-steps additively, then design versatility and optical variability are improved, but device complexity and production time increase

Engineering Contradiction:
Improvedesign versatilityVSAvoidproduction process complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent divides the relief structure creation into multiple sub-steps, where each sub-step deposits or cures a specific layer or portion of the relief elements. This segmentation allows precise control over relief element geometry, height, and orientation, enabling complex optically variable designs while organizing the production process into manageable, automated stages that reduce operational complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary digital modeling and process planning before physical production. The relief structure geometry, material selection, and printing parameters are predetermined through computer simulation and optimization, allowing multiple sub-steps to be executed automatically without complex manual intervention, thus reducing device complexity while maintaining design versatility.

Inventive Principle:
Principle #10Preliminary action

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 approach enables the production of optically variable elements with enhanced visual variability and security features, suitable for valuables and branded items, by creating relief structures with locally different heights and angles, which can be applied directly or transferred to substrates, offering improved security and design options.

Implementation Method 1

The relief elements are produced by means of an additive method, in particular by printing, with several sub-steps of the additive method being carried out for the relief elements and the relief shape of the relief element being determined by the sub-steps

Methodology Applied
Scientific Effect3D Printing: 3D Printing

Implementation Method 2

printing can be carried out by means of an inkjet method, with (UV) curable ink preferably being printed and (UV) cured

Methodology Applied
Scientific EffectPhotopolymerisation: Photopolymerisation

Implementation Method 3

The relief elements can be created by means of (laser) stereolithography. As an alternative to printing, the relief form could be produced additively by means of selective laser sintering when creating the relief elements

Methodology Applied
Scientific EffectSelective Laser Sintering: Selective Laser Sintering

Implementation Method 4

The relief elements can be created by means of (laser) stereolithography

Methodology Applied
Scientific EffectLaser Ablation: Laser Ablation

Data Source

PatentEP3687826B1Method for producing an optically variable element, and corresponding element
Publication Date: 2021.09.08 GIESECKE & DEVRIENT CURRENCY TECHNOLOGY GMBH
  • EP3687826B1 patent drawingFigure 1~2c
  • EP3687826B1 patent drawingFigure 3a~4
  • EP3687826B1 patent drawingFigure 5a~7b

AI summary

The invention relates to a method for producing an optically variable element, the method comprising the following steps: creating a relief structure formed from a plurality of relief elements (11, 12) lying side by side in a plane, wherein the relief elements have a relief form that is non-parallel to the plane; and selectively modifying the relief structure, wherein the modification and the relief form of the relief elements are matched in such a way that for the viewer, the modified relief structure shows different representations depending on the viewing angle. The relief structure is created by means of an additive method, wherein multiple sub-steps of the additive method are executed for each relief element (11, 12), and the sub-steps for the relief element (11, 12) determine the relief form of the relief element.