Security Element with Segmented Hologram and Luminescent Imprint
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing security elements with reflection holograms and luminescent imprints under UV radiation suffer from visual impairment and reduced protection against forgery due to optical interference between the two features, making them difficult to distinguish and less effective.
Innovation Solution
Incorporating a halftone print image with luminescent inks and creating a see-through region by recesses in the reflection layer free from diffraction structures above the imprint, allowing unimpaired passage of isotropic fluorescent radiation and reducing optical disturbances, thereby enhancing the visual separability and protection against forgery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a reflection hologram and luminescent imprint are combined in a security element, then the protection against forgery is enhanced through multiple security features, but the visual distinguishability deteriorates due to optical interference and mutual impairment between the two features
Solution Approach 1:
The security element is segmented into distinct functional regions: a first region containing the reflection hologram with diffraction structures and a second region containing the luminescent imprint without diffraction structures. This spatial segmentation allows each security feature to function independently without optical interference, resolving the contradiction between enhanced security and visual distinguishability.
Solution Approach 2:
Different regions of the security element have different optical properties: the first region has diffraction structures for holographic effects while the second region is free from diffraction structures to allow pure luminescence. This local differentiation ensures that each security feature maintains its visual characteristics without being impaired by the other.
2Adaptability or versatility
If a luminescent imprint is placed under a reflection layer with diffraction structures, then both security features are integrated in one element, but optical disturbances such as Moiré patterns and blurring occur that reduce the clarity of the security features
Solution Approach 1:
The security element is divided into a first region with diffraction structures for the reflection hologram and a second region without diffraction structures for the luminescent imprint. This segmentation prevents optical disturbances like Moiré patterns and blurring by ensuring that the isotropic fluorescent radiation from the luminescent imprint passes through without being diffracted, while the reflection hologram maintains its diffraction-based visual effects in the separate first region.
3Reliability
If the reflection layer is made transparent to allow the luminescent imprint to shine through, then the second security feature becomes visible under UV light, but the visual separability of the two security features deteriorates due to visual mixing
Solution Approach 1:
The security element is segmented into a first region containing the reflection hologram and a second region containing the luminescent imprint. The reflection layer is configured to be transparent in the second region to allow UV-induced luminescence to pass through, while maintaining its reflective and diffractive properties in the first region. This spatial segmentation prevents visual mixing and maintains clear visual separability between the two security features.
Solution Approach 2:
The reflection layer exhibits different optical properties in different regions: in the first region it provides reflection and diffraction for the hologram, while in the second region it is transparent to allow luminescent light to pass through. This local differentiation ensures both visibility of the luminescent feature and clear visual separability from the holographic feature.
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
This configuration significantly increases the protection against forgery by maintaining the clarity of both security features, reducing optical disturbances, and enhancing the spatial depth effect, while ensuring the luminescent imprint remains recognizable only under UV light, thus providing a robust security element.
Implementation Method 1
at least one imprint which is luminescent under UV radiation and which forms a second security feature that is recognisable under UV light
Implementation Method 2
at least one embossed diffraction structure, at least one reflection layer which optically interacts with the diffraction structure in order to form a reflection hologram
Data Source
AI summary
A value document having a security element in the form of a strip with a first polymer layer which comprises at least one embossed diffraction structure, having at least one reflection layer which visually interacts with the diffraction structure in order to form a reflection hologram as the first visually recognisable security feature, and having at least one imprint which is luminescent under UV radiation and which forms a second security feature that is visually recognisable under UV light, wherein the reflection hologram comprises at least one see-through region on the second security feature. In order to increase the level of protection against forgery of the security element, the luminescent imprint comprises a halftone print image, and the see-through region is formed by at least one recess in the reflection layer and by the polymer layer which is free in this region of the recess from the diffraction structure at least above the halftone print image of the imprint.