Security Element With Segmented Reflective Layer
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Solution Overview
Problem
Existing security elements with multi-layer structures capable of causing interference are expensive to produce and require complex laser demetallization processes, limiting their effectiveness in protecting against counterfeiting and not allowing information to be visible in transmitted light.
Innovation Solution
Incorporating gaps in both the reflective and partially transparent layers, arranged in a pattern or grid-like manner, to create a security element where the pattern visible in reflected light disappears in transmitted light, allowing for more complex structures and additional security features like fluorescence or microstructures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If laser demetallization is used to change the partially transparent layer, then the optically variable effect is achieved, but the production cost increases and the process complexity increases
Solution Approach 1:
The patent divides the reflective layer into multiple segments (first reflective layer and second reflective layer) separated by a gap, allowing different optical functions to be distributed across layers rather than requiring complex modification of a single layer structure
Solution Approach 2:
The patent extracts the optically variable function from the reflective layer and places it in the dielectric layer with optically variable thickness, removing the need for complex laser demetallization processes on metal layers
2Loss of information
If the reflective layer is structured to create patterns, then information visible in reflected light is achieved, but the same structure must be visible in transmitted light, reducing security
Solution Approach 1:
The reflective layer is segmented into first and second reflective layers separated by a gap, with the dielectric layer containing the optically variable structure. This segmentation allows the security information to be visible in reflected light through the first reflective layer while the gap and second reflective layer prevent the same information from being visible in transmitted light
Solution Approach 2:
The patent moves the optically variable structure from the reflective layer to the dielectric layer, creating a three-layer configuration where the optically variable dielectric layer is positioned between the two reflective layers. This dimensional arrangement enables differential visibility - the structure is visible in reflected light but hidden in transmitted light due to the positioning and optical properties of the layers
3Illumination intensity
If optically variable pigments are used, then color change effect is achieved, but production cost increases significantly
Solution Approach 1:
The patent replaces complex optically variable pigments with a simpler structural solution - a dielectric layer with optically variable thickness created by controlled deposition processes. This substitutes material complexity with structural simplicity, achieving the same color shift effect at lower production cost
Solution Approach 2:
The patent achieves optically variable effects by changing the physical parameter of layer thickness in the dielectric layer rather than using complex pigment compositions. The thickness variation (50-200 nm) creates the color shift through interference effects, providing a cost-effective alternative to expensive optically variable pigments
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
Enhances security against counterfeiting by providing a visible effect in reflected light that is not apparent in transmitted light, reducing production costs and improving the visibility of information on data carriers like banknotes and cards.
Implementation Method 1
The color shift is caused by an interference effect between the light rays reflected from the surface of the outer semi-transparent layer and the light rays that pass through the outer semi-transparent and middle dielectric layers and are reflected back to the semi-transparent layer by the inner reflective layer
Implementation Method 2
The light beams are then either transmitted outwards or reflected again at the partially transparent layer, so that in this case the light beams are reflected back and forth multiple times between the reflecting layer and the partially transparent layer
Data Source
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AI summary
The invention relates to a security element comprising at least one thin-film element in the form of a multilayer structure that can be subject to interference. Said multilayer structure that can be subject to interference consists of at least one reflective layer, at least one semipermeable layer, and at least one dielectric layer which is arranged therebetween. According to the invention, the security element has a plurality of recesses in the reflective layer in a first zone while having at least one recess or a plurality of recesses in the semipermeable layer in a second zone. At least part of the second zone is arranged within the first zone, and the total area of the second zone, at least part of which is arranged in the first zone, is smaller than the total area of the first zone, such that when the security element is viewed from the semipermeable layer, the visible image in front illumination is different from the visible image in rear illumination.