Security Element with Adjoining Optically Variable Coatings
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Solution Overview
Problem
Current security elements for documents of value lack sufficient protection against forgery, as they do not provide adequate visual differentiation when viewed from different angles or under varying lighting conditions.
Innovation Solution
A security element with a transparent plastic film substrate featuring an optically variable coating and a further multi-layer structure that includes semi-transparent mirror layers and a dielectric layer, which exhibits a metallic hue in reflected light and a colorful hue in transmitted light, enhancing visual perception and security features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single optically variable coating is applied to the substrate, then the security element provides basic visual differentiation, but the protection against counterfeiting remains insufficient
Solution Approach 1:
The patent combines two distinct optically variable coatings on a single substrate, where each coating exhibits different optical properties and color responses. This merging of multiple security features into one element enhances anti-counterfeiting protection while maintaining a unified structure that does not significantly increase complexity.
Solution Approach 2:
The security element uses composite coating structures with different material compositions - one coating containing metal flakes for golden/bronze hues and another containing interference pigments for color-shifting effects. These composite material layers work together to create a multi-layered security feature that is difficult to replicate.
2Ease of operation
If the security element uses simple coating structures, then the manufacturing process remains straightforward, but the visual differentiation when tilted or viewed from different angles is insufficient
Solution Approach 1:
The patent employs two coatings that display different color changes under varying viewing conditions. The first coating transitions between golden and bronze hues, while the second coating exhibits color-shifting effects across multiple wavelengths. This dual-color-change mechanism provides clear visual differentiation that is easily perceptible when the element is tilted or viewed from different angles.
Solution Approach 2:
The security element incorporates dynamic optical responses where the coatings actively change appearance based on viewing angle and lighting conditions. The metal flake coating creates dynamic reflections that shift with orientation, while the interference coating produces dynamic color transitions, making the element visually engaging and difficult to counterfeit.
3Reliability
If a further coating with metallic and colorful hues is applied, then the visual appearance becomes more distinct when tilted, but the manufacturing precision requirements increase
Solution Approach 1:
The patent utilizes controlled variations in layer parameters such as thickness and composition to achieve the desired optical effects. By carefully adjusting the thickness of the metal flake layer and the interference coating layers, the element produces distinct golden/bronze and color-shifting hues that provide strong authentication features while maintaining manufacturability through standardized parameter ranges.
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 enhanced security element significantly increases protection against forgery by providing a more distinct visual appearance when tilted or viewed from different sides, making it difficult to replicate, thus improving document authenticity.
Implementation Method 1
an interference-capable, multilayer structure consists of a reflective layer, a dielectric layer, and a partially transparent layer... Due to its mode of operation, such a security feature is also referred to as a thin-film interference layer structure or a color-shift element
Implementation Method 2
When measuring the transmission of unpolarized light in the blue wavelength range from 420 nm to 490 nm, the further coating exhibits a resonance with a full width at half maximum (FWHM) of 70 nm to 150 nm
Implementation Method 3
the further coating is formed by a further multilayer structure comprising at least two semitransparent mirror layers and at least one dielectric layer arranged between the at least two mirror layers
Data Source
Figure 1~1b
Figure 2~2c
AI summary
The invention relates to a security element for security papers, value documents, or the like, which has a transparent or translucent substrate composed of a plastic film, wherein a metal or optically variable coating is applied to the substrate. According to the invention, a further coating is applied to the substrate, wherein the metal or optically variable coating and the further coating are arranged in such a way that the metal or optically variable coating and the further coating adjoin each other or at least partially overlap. The further coating has a colored layer or a multilayer structure, wherein the colored layer and the multilayer structure are designed in such a way that the colored layer and the multilayer structure exhibit a metallic, preferably golden or bronze-colored shade in incident light and a colorful, preferably blue or green shade in transmitted light. Transmitted light exists when an object is illuminated from one side and observed from the other side. Incident light exists when an object is illuminated and observed from the same side.