See-through Security Element with Microstructures

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Solution Overview

Problem

Existing security elements for documents of value lack effective protection against forgery, particularly in terms of visibility under varying lighting conditions and angle-dependent authenticity verification.

Innovation Solution

A see-through security element with a microstructure formed from a multiplicity of structural elements arranged with a characteristic spacing of 1 μm or more, applied to a transparent or translucent substrate, which changes appearance when viewed from different angles, incorporating a marking layer with embossed or printed microstructures and coatings for enhanced optical variability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If existing security elements are used for documents of value, then basic security protection is provided, but they lack effective protection against forgery and require special lighting conditions for authenticity verification

Engineering Contradiction:
Improveprotection against forgeryVSAvoidvisibility under varying lighting conditions
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent employs optical variable elements that change color or brightness impression depending on the viewing angle. The microstructures with spacing of 1 μm or more create angle-dependent optical effects that are easily recognizable without special lighting conditions, resolving the contradiction between security reliability and ease of verification

Inventive Principle:
Principle #32Color changes

Solution Approach 2:

The patent changes the physical parameters of the security element by controlling the microstructure spacing to be 1 μm or more, which optimizes the optical effects for visibility under normal lighting conditions while maintaining high security against forgery through angle-dependent visual appearance

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If microstructures with smaller spacing are used to enhance optical effects, then visual appearance changes with viewing angle, but the structure becomes difficult to reproduce and manufacture

Engineering Contradiction:
Improveoptical variabilityVSAvoidmanufacturing complexity
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent optimizes the microstructure spacing parameter to 1 μm or more, which maintains strong optical variability effects while being manufacturable with standard techniques. This parameter optimization resolves the contradiction between optical adaptability and manufacturing ease

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The security element is segmented into multiple microstructures with specific spacing, creating angle-dependent optical effects that are both visually impressive and manufacturable using conventional embossing or printing techniques on transparent substrates

Inventive Principle:
Principle #1Segmentation

3Reliability

If thicker security elements are used to incorporate multiple security features, then protection against forgery is enhanced, but the element becomes less suitable for use in documents

Engineering Contradiction:
Improvesecurity protectionVSAvoidthickness
Core Design Contradiction:
ReliabilityVSLength of stationary object

Solution Approach 1:

The patent uses composite structures combining transparent or translucent substrate materials with integrated microstructures and optical variable elements. This composite approach provides multiple security features in a thin profile suitable for document embedding, resolving the contradiction between security reliability and dimensional constraints

Inventive Principle:
Principle #40Composite materials

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 level of protection against forgery and ensures easy recognition of optical information without requiring special lighting, with the thin design allowing for use in documents and offering visually appealing movement effects that enhance security and authenticity verification.

Implementation Method 1

a microstructure with a visual appearance that is dependent on the viewing angle when viewed through... the at least one microstructure is formed from an arrangement of a multiplicity of structure elements with a characteristic structure spacing of 1 μm or more

Methodology Applied
Scientific EffectOptical diffraction: Diffraction

Implementation Method 2

The see-through security element preferably has a transparent or translucent substrate... the transparency must be at least high enough for the viewer to be able to perceive the appearance, which depends on the viewing angle, in transmitted light

Methodology Applied
Scientific EffectLight transmission: Light

Data Source

PatentEP2939845B1See-through safety element with microstructures
Publication Date: 2018.05.02 GIESECKE & DEVRIENT CURRENCY TECHNOLOGY GMBH
  • EP2939845B1 patent drawingFigure 1~2
  • EP2939845B1 patent drawingFigure 3~4b
  • EP2939845B1 patent drawingFigure 5~6

AI summary

The invention relates to a see-through security element (12) for security documents, valuables, and the like, comprising at least one microstructure with a visual appearance (26, 28) that is dependent on the viewing angle when viewed through it. According to the invention, the at least one microstructure is formed from an arrangement of a plurality of structural elements (24) with a characteristic structural spacing of 1 µm or more, and the see-through security element (12) has a total thickness of 50 µm or less.