Achromatic Diffractive Security Element for Forgery Resistance
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Solution Overview
Problem
Current security elements for securities and security papers lack enhanced anti-counterfeit measures, as diffractive structures often appear colored and can be easily replicated, compromising their authenticity.
Innovation Solution
A security element featuring optically effective, diffractive structures that appear achromatic to the naked eye but can be verified as diffractive through optical measurements, utilizing irregularly arranged and additive color-mixed structures, potentially with an optical effect layer and embossed design, to enhance forgery resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If diffractive structures are used for security features, then optical effects are enhanced, but the structures appear colored and can be easily replicated
Solution Approach 1:
The patent applies color changes by using diffractive structures that produce achromatic (colorless) optical effects instead of the traditional colored iridescent effects. This is achieved through specific structural designs that diffract light without producing visible color separation, making the security feature appear colorless to the naked eye while maintaining diffractive properties that can be verified with appropriate optical equipment
Solution Approach 2:
The patent changes the optical parameters of the diffractive structures by adjusting the grating period, depth, and shape to achieve achromatic diffraction. By carefully controlling these structural parameters, the diffractive structures produce white or colorless appearance in the visible spectrum while maintaining their diffractive character for verification purposes
2Reliability
If reflective structures are used to achieve achromatic appearance, then security against counterfeiting is improved, but the diffractive character cannot be verified
Solution Approach 1:
The patent segments the verification process into two distinct levels: visual inspection level (achromatic appearance to naked eye) and instrumental verification level (diffractive character detection using optical equipment). This segmentation allows the security feature to serve dual purposes - aesthetic/security appearance and verifiable authenticity - without compromising either function
3Ease of manufacture
If diffractive structures with regular arrangement are used, then manufacturing is simplified, but the security element is more susceptible to counterfeiting
Solution Approach 1:
The patent applies asymmetry by using irregular arrangements of diffractive structures with varying parameters (grating periods, depths, shapes) across different regions. This irregularity makes each security element unique and difficult to replicate, while still maintaining overall achromatic appearance. The asymmetric distribution of structural parameters provides inherent security against counterfeiting
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 achromatic appearance significantly increases security against forgery, as the diffractive nature remains undetectable to the unaided eye but can be confirmed using high-resolution microscopes, providing robust authenticity verification.
Implementation Method 1
Diffractive structures, on the other hand, cause light diffraction and are therefore usually perceived as iridescent optical effects due to their optical appearance. These include classic holographic motifs.
Data Source
Figure 1
AI summary
The invention relates to a security element (1) in particular for securities, security papers or security items, such as banknotes, identity cards, credit cards, wherein the security element (1) has at least one area (2) with optically effective, diffractive structures (3), wherein an overall impression produced by the optically effective, diffractive structures (3) appears achromatic to an unarmed eye.