Multilayer Security Element Metal Layer Masking
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Solution Overview
Problem
Conventional methods for producing structured metal layers in optical security elements face challenges in achieving precise registration and accuracy due to thermal and mechanical distortions, leading to tolerance fluctuations across the surface, which complicates the production of secure, forgery-proof multi-layer bodies.
Innovation Solution
A method involving a multi-layer body production process where a single or multi-layer decorative layer is applied to a carrier layer, followed by a metal layer with varying thickness zones, and subsequent structuring using the metal layer as a mask for the decorative layers, allowing for precise registration without additional registration devices, thereby compensating for distortions and maintaining accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional methods (sputtering, vapor deposition, etching, laser ablation) are used to create structured metal layers, then the metal layer can be structured with fine features, but the registration accuracy deteriorates due to thermal and mechanical distortions causing tolerance fluctuations
Solution Approach 1:
The patent applies the preliminary action principle by pre-structuring the substrate with relief structures (such as embossed patterns, gratings, or holograms) before applying the metal layer. This pre-structured substrate serves as a stable reference framework that compensates for subsequent thermal and mechanical distortions during metal layer deposition and etching processes, maintaining registration accuracy throughout manufacturing
Solution Approach 2:
The patent employs parameter changes by varying the thickness of the metal layer across different zones (first zones with first thickness, second zones with second thickness) and adjusting the relief structure parameters on the substrate. These parameter variations enable differential optical effects while maintaining precise layer alignment despite process distortions
2Manufacturing precision
If multiple manufacturing steps are required to produce the security element, then fine structured features can be achieved, but the registration accuracy deteriorates due to cumulative alignment errors
Solution Approach 1:
The patent merges multiple functions into the metal layer: it serves as both the decorative/security feature layer and the mask layer for structuring the decorative layers. This consolidation eliminates separate masking steps and reduces the number of registration operations required, improving both alignment accuracy and production efficiency
Solution Approach 2:
The metal layer is designed with multi-functionality, acting as a reflective layer for optical security features, a mask for subsequent etching or exposure processes, and a structural element defining first and second zones with different thicknesses. This universal application reduces the total number of process steps and registration operations needed
3Manufacturing precision
If additional registration devices are used to improve alignment accuracy, then the registration precision improves, but the device complexity and production cost increase
Solution Approach 1:
The patent implements self-service by designing the substrate and metal layer with inherent registration features (relief structures and thickness variations) that automatically provide alignment references for subsequent processing steps. The first and second zones with different metal layer thicknesses serve as self-aligning masks, eliminating the need for external registration devices or complex alignment systems
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 method ensures precise registration and accuracy of layers, reducing tolerance fluctuations to the micrometer range, making the multi-layer body highly secure against forgery and difficult to reproduce, with the metal layer serving multiple functions as a mask and exposure tool.
Implementation Method 1
Creating a structured metal layer from a metal layer applied over a surface, for example by sputtering or vapor deposition
Implementation Method 2
Creating a structured metal layer from a metal layer applied over a surface, for example by sputtering or vapor deposition
Implementation Method 3
the metal layer serves as a mask during the production of the multilayer body, preferably as an exposure mask for exposure, i.e., the photoactivation of a photoactivatable layer
Data Source
Figure 1a~1b
Figure 1c~1d
Figure 2a~2b
AI summary
The invention relates to a method for producing a multilayer element (100, 200, 300, 400) and to a multilayer element (100, 200, 300, 400) produced using said method. A single-layer or multi-layer first décor layer (3) is applied to a carrier layer having a first side (11) and a second side (12). A metal layer (5) is applied to the side of the first décor layer (3) facing away from the carrier layer and is structured such that the metal layer (5) has a first thickness in one or more first zones (8) and a second thickness, different from the first thickness, in one or more second zones (9), wherein the second thickness is in particular equal to zero. A single-layer or multi-layer second décor layer (7) is applied to the side of the metal layer (5) facing away from the first décor layer (3), and using the metal layer (5) as a mask, is structured in such a manner that the first décor layer (3) and/or second décor layer (7) is at least partially removed in the first zones (8) or second zones (9).