Photoluminescent Security Element in Multilayer Window Structure
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Solution Overview
Problem
Existing security features in identification documents, such as multilayer structures, are limited in manufacturing flexibility and difficulty in combining with other security features, making them vulnerable to counterfeiting.
Innovation Solution
A secure multilayer structure is developed with a photoluminescent security element positioned between the base layer and the masking layer, adjacent to the window edge, allowing the security element to be masked and only visible when illuminated through the window edge, enabling authentication and combining with other security features like laser-engraving and printing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the security element is exclusively contained within the periphery (edge) of the identification document, then the security feature can be detected by illuminating the edge, but the manufacturing flexibility is limited and it is difficult to combine with other security features
Solution Approach 1:
The security element is positioned within the window area rather than exclusively at the edge, utilizing the two-dimensional space of the window to place the photoluminescent material. This dimensional repositioning allows the security element to be integrated with other security features across the document surface while maintaining detectability through the window edge illumination method.
2Adaptability or versatility
If the security element is positioned within the window area, then manufacturing flexibility is improved and combination with other security features is enabled, but the security element must be masked to remain invisible when not illuminated
Solution Approach 1:
A masking layer is introduced as an intermediary component between the photoluminescent security element and the external environment. This masking layer selectively blocks light paths, ensuring the security element remains invisible during normal viewing but becomes visible when illuminated through the window edge, thus enabling its integration without compromising document appearance.
Solution Approach 2:
The masking layer is designed with spatially varying properties, being opaque in certain regions to mask the security element and transparent in other regions to allow illumination. This local differentiation of optical properties enables the security element to be hidden when not needed while remaining detectable under specific illumination conditions.
3Reliability
If the masking layer is made substantially opaque to the re-radiated luminescent light, then the security element is forced to emerge through the covering layer, but the overall light transmission is reduced
Solution Approach 1:
The masking layer is designed with spatially varying optical properties, being opaque in certain regions to mask the security element and transparent in other regions to allow illumination. This local differentiation of optical properties enables the security element to be hidden when not needed while remaining detectable under specific illumination conditions.
Solution Approach 2:
The window area is segmented into different functional zones: regions where the masking layer is opaque to control security element visibility, and regions where it is transparent to allow light transmission. This segmentation of the window area into distinct optical zones resolves the contradiction between security element masking and light transmission.
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 enhances manufacturing flexibility, allows for easier integration with other security features, and significantly increases the difficulty of counterfeiting by making the security element visible only under specific illumination, thus improving the authenticity verification process.
Implementation Method 1
a security element comprising a photoluminescent material multilayer structured between a core layer of the multilayer structure and a second layer of the multilayer structure such that the presence of the security element can be checked by illuminating the edge connecting the core and second layers of the multilayer structure and viewing the re-radiated luminescent light emerging from the core layer through the at least one edge
Data Source
Figure 1~2
Figure 3~4
AI summary
A secure multilayer structure, comprising a base layer, a first masking layer comprising a window opened in the first masking layer, said window comprising an edge, and a security element including a photoluminescent agent positioned between the base layer and the first masking layer, adjacent to the window edge, the security element configured such that when the window edge is illuminated, the photoluminescent agent re-radiates luminescent light via the window.