Microstructure Production via Selective Viscous Printing

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Solution Overview

Problem

Current methods for producing microstructures on carriers for security elements, such as moiré magnification arrangements, face challenges in achieving high resolution and preventing impairment of the visual impression due to toning films and unevenness during printing.

Innovation Solution

A method involving a carrier with a relief structure having elevations and depressions, where a high-viscosity imprint material is selectively transferred to the elevations or depressions using a printing tool, with precise control over layer thickness and pressure to avoid toning and ensure evenness, and optionally using a laminating film for protection and bonding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional printing methods are used to produce microstructures, then the production process is simple, but the manufacturing precision and visual impression are impaired due to toning films and unevenness

Engineering Contradiction:
Improvemicrostructure resolutionVSAvoidprinting process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent changes the viscosity parameter of the printing material to a high viscosity range (10-200 Pa·s, preferably 800-1500 mPa·s) to prevent the material from flowing into depressions and forming toning films. This parameter change enables precise printing on relief structures while maintaining simple conventional printing processes, thus resolving the contradiction between manufacturing precision and device complexity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a relief structure with elevations and depressions before printing, where the elevations are designed to be higher than the intended print layer thickness. This preliminary structuring action ensures that high-viscosity printing material applied later will only deposit on elevations, preventing toning film formation and achieving high-resolution microstructures without complex printing equipment

Inventive Principle:
Principle #10Preliminary action

2Reliability

If printing material is transferred to depressions, then complete coverage is achieved, but toning films form on raised areas impairing visual impression

Engineering Contradiction:
Improvevisual impression qualityVSAvoidprinting material distribution
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent applies printing material selectively to specific locations (elevations) rather than uniformly across the entire surface. The high-viscosity material is confined to elevation areas due to its resistance to flow, creating local quality differentiation where elevations are printed and depressions remain unprinted or minimally printed, thus preventing toning films on raised areas while maintaining visual impression quality

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

By changing the viscosity parameter of the printing material to high values, the patent controls the distribution quantity and location of the material. The high viscosity prevents material from flowing into depressions, ensuring material is deposited only where needed (on elevations) without forming unwanted toning films, thus resolving the contradiction between reliable visual quality and material distribution control

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If low viscosity printing material is used, then easy transfer is achieved, but the material flows into depressions causing unevenness

Engineering Contradiction:
Improveprinting material transferVSAvoidmicrostructure evenness
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent changes the viscosity parameter from low to high (10-200 Pa·s range) to prevent material flow into depressions. Despite the higher viscosity, the material remains transferable through conventional printing methods because the relief structure elevations provide sufficient contact area. This parameter change resolves the contradiction by enabling easy transfer while maintaining microstructure evenness and precision

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

This method allows for the creation of high-resolution microstructures with enhanced visual effects and security features, such as optically variable effects, while maintaining the integrity of the microstructure and preventing re-dissolving in subsequent processes.

Implementation Method 1

the viscosity of the printing material is selected such that the printing material is selectively transferred either substantially only onto the raised areas or substantially only into the depressions of the relief structure

Methodology Applied
Scientific EffectViscosity:

Implementation Method 2

the substrate is provided with an embossed structure having raised areas and depressions forming the relief structure

Methodology Applied
Scientific EffectEmbossing:

Data Source

PatentEP2240330B1Method for producing a microstructure
Publication Date: 2019.05.29 GIESECKE & DEVRIENT CURRENCY TECHNOLOGY GMBH
  • EP2240330B1 patent drawingFigure 1~2b
  • EP2240330B1 patent drawingFigure 3~5
  • EP2240330B1 patent drawingFigure 6a~6c

AI summary

The invention relates to a method for producing a microstructure on a carrier (22), in which a carrier (22) is provided with a relief structure (26, 28) having elevations (26) and depressions (28), and in which the elevations (26) and/or depressions (26) are arranged in the form of the desired microstructure, and an imprint substance (30; 34) is transferred onto the relief structure (26, 28) by means of a printing tool, wherein the viscosity of the imprint substance (30; 34) is chosen in such a way that the imprint substance (30; 34) is transferred selectively either substantially only onto the elevations (26) or substantially only into the depressions (28) of the relief structure.