Security Element with Aligned Micromirrors and Diffractive Structures

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Solution Overview

Problem

Current security elements for documents of value lack effective protection against counterfeiting and do not provide an attractive visual appearance, as they can be reproduced using modern copiers, and existing optically variable elements do not offer sufficient complexity to prevent unauthorized duplication.

Innovation Solution

A security element featuring a carrier with an embossing lacquer layer having a diffractive structure and a micromirror arrangement, where a reflection layer and a colored thin-film element are spatially aligned along the relief structures, combined with a method involving the use of soluble wash inks and vapor deposition to create a multi-layer structure that changes appearance with viewing angle, providing enhanced protection and visual appeal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional security elements are used, then they can be reproduced using modern copiers, but they lack effective protection against counterfeiting

Engineering Contradiction:
Improvecounterfeit protectionVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The security element is divided into multiple functional layers: a base layer with micromirror arrangement, an intermediate layer with diffractive structure, and a top layer with color-shifting thin-film elements. Each layer performs a specific optical function that contributes to the overall anti-counterfeiting effect, making the system more complex but highly effective against reproduction

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent combines multiple materials with different optical properties: reflective micromirrors, diffractive optical elements, and interference-based color-shifting films. This composite structure creates multiple simultaneous optical effects (reflection, diffraction, interference) that are difficult to reproduce with conventional copying methods

Inventive Principle:
Principle #40Composite materials

2Ease of manufacture

If simple security features are used, then they are easy to manufacture, but they do not provide attractive visual appearance

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidvisual appearance quality
Core Design Contradiction:
Ease of manufactureVSIllumination intensity

Solution Approach 1:

The patent utilizes changes in optical parameters (viewing angle, light wavelength, polarization) to create dynamic visual effects. The color-shifting thin-film elements change appearance based on viewing angle due to interference effects, and the diffractive structure disperses light to create rainbow patterns, providing attractive visual appearance through parameter-dependent effects rather than complex manufacturing

Inventive Principle:
Principle #35Parameter changes

3Reliability

If optically variable elements are used, then they provide viewing-angle-dependent effects, but they do not offer sufficient complexity to prevent unauthorized duplication

Engineering Contradiction:
Improveanti-counterfeiting effectivenessVSAvoidoptical structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges three distinct optical technologies into a single security element: micromirror arrays for directional reflection, diffractive optical elements for wavelength separation, and thin-film interference structures for color-shifting effects. This combination creates a multi-layered optical system where each component contributes to the overall complexity and anti-counterfeiting effectiveness

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The security element exploits multiple optical dimensions simultaneously: spatial dimension (micromirror arrangement patterns), angular dimension (viewing-angle-dependent color shifts), and spectral dimension (diffractive rainbow patterns). This multi-dimensional approach significantly increases the complexity required for unauthorized duplication

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 provides a high degree of protection against counterfeiting by creating a security element that changes color or appearance with viewing angle, making it difficult to reproduce accurately, while also offering an attractive visual effect, thus enhancing the security and authenticity of documents.

Implementation Method 1

printing the first relief structure forming a diffractive structure with a printing ink based on platelet-shaped metal pigments, which are such that they align themselves spatially along the relief structure of the embossed varnish layer and thereby form a reflective layer

Methodology Applied
Scientific EffectAlignment of platelet-shaped particles:

Implementation Method 2

printing a soluble wash ink in such a way that the areas of the first relief structure forming a diffractive structure and the second, a relief structure forming a micromirror arrangement, creating recesses in the applied wash paint

Methodology Applied
Scientific EffectSolubility and washing:

Implementation Method 3

the full-surface application of a colored thin-film element followed by washing off the wash paint together with the area of the colored thin-film element created above the wash paint, so that the colored thin-film element remains in the areas of the first relief structure forming a diffractive structure and the second relief structure forming a micromirror arrangement in a shape spatially oriented along the respective relief structure

Methodology Applied
Scientific EffectThin-film deposition: Deposition (physical)

Implementation Method 4

a first relief structure forming a diffractive structure

Methodology Applied
Scientific EffectDiffraction: Diffraction

Implementation Method 5

a second relief structure forming a micromirror arrangement

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 6

the colored thin-film element provided in step d) is a color-shifting thin-film element that conveys different color impressions to the viewer at different viewing angles

Methodology Applied
Scientific EffectInterference: Interference

Implementation Method 7

a semi-transparent thin-film element that conveys different color impressions to the viewer when viewed in reflected light and when viewed in transmitted light

Methodology Applied
Scientific EffectTransparency and light transmission:

Data Source

PatentEP3337675B1Security element, method for producing same, and data carrier equipped with the security element
Publication Date: 2019.11.13 GIESECKE & DEVRIENT CURRENCY TECHNOLOGY GMBH
  • EP3337675B1 patent drawingFigure 1~4
  • EP3337675B1 patent drawingFigure 5~8
  • EP3337675B1 patent drawingFigure 9~12

AI summary

The invention relates to a method for producing a security element, comprising the steps of: a) providing a support which has an embossing lacquer layer that has a first, diffractive structure-forming relief structure, and a second, micromirror arrangement-forming relief structure; b) imprinting the first, diffractive structure-forming relief structure with a printing ink which is based on metallic platelet pigments that are designed in such a way that they spatially align themselves along the relief structure of the embossing lacquer layer; c) imprinting with a soluble wash ink such that the regions of the first, diffractive structure-forming relief structure and the second, micromirror arrangement-forming relief structure form recesses in the applied wash ink; d) applying a colored thin-film element over the whole surface and then washing off the wash ink such that the colored thin-film element remains in the regions of the first, diffractive structure-forming relief structure and the second, micromirror arrangement-forming relief structure in a fashion spatially aligned along the respective relief structure; and e) applying an adhesive layer.