Security Element With Refractive Index Matching
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Solution Overview
Problem
Existing security elements with color-shift effects and optically variable relief patterns face challenges in maintaining their authenticity and preventing counterfeiting, as the visual effects can interfere with each other, compromising their distinct appearance and security.
Innovation Solution
A security element is developed with a thin-film element and a relief pattern in an embossing lacquer layer, where the embossing lacquer layer is metalized in sub-regions and leveled with a transparent lacquer layer of matching refractive index, ensuring the color-shift effect and optically variable effect are visible independently without interference, and the transparent lacquer layer is applied thick enough to adhere well to other layers for enhanced durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If both color-shift effect and relief pattern are included in the security element, then the visual appearance and security are improved, but the two optical effects interfere with each other, compromising their distinct appearance
Solution Approach 1:
The security element is divided into distinct functional regions: a first region containing the color-shift effect and a second region containing the relief pattern. This spatial segmentation allows each optical effect to be displayed independently without mutual interference, while both regions are integrated into a single security element structure.
Solution Approach 2:
Different regions of the security element are assigned different optical properties and functions. The first region is optimized for color-shift effect with specific thin-film structures, while the second region is optimized for relief pattern display with appropriate embossing characteristics. This local differentiation ensures each effect maintains its distinct visual appearance.
2Manufacturing precision
If the transparent lacquer layer is applied to level the relief pattern, then the visual appearance and register alignment are improved, but the layer thickness and manufacturing complexity increase
Solution Approach 1:
A transparent lacquer layer is introduced as an intermediary between the relief pattern layer and the color-shift effect layer. This intermediate layer serves multiple functions: it levels the relief pattern to create a flat surface, provides optical transparency to maintain visibility, and facilitates precise register alignment between different security features without requiring direct contact between the relief pattern and color-shift layers.
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 allows for a secure, high-stability security element where the color-shift and relief pattern effects appear in perfect register without interference, enhancing the security and durability against mechanical and chemical vulnerabilities, while maintaining an attractive visual appearance.
Implementation Method 1
a thin-film element having a color-shift effect... whose color impression for the viewer changes with the viewing angle, and when the security feature is tilted, shifts for example from green to blue, from blue to magenta or from magenta to green
Implementation Method 2
the relief pattern of the partially metalized embossing lacquer layer is leveled with a transparent lacquer layer whose refractive index substantially corresponds to the refractive index of the embossing lacquer layer
Data Source
AI summary
The present invention relates to a security element (20) for securing valuable articles, in whicha thin-film element (32) having a color-shift effect and a relief pattern (26) present in an embossing lacquer layer (24) are stacked,the embossing lacquer layer (24) having the relief pattern (26) is metalized (28) in sub-regions, andthe relief pattern (26) of the partially metalized embossing lacquer layer (24, 28) is leveled with a transparent lacquer layer (30) whose refractive index substantially corresponds to the refractive index of the embossing lacquer layer (24).