Partially Demetallised Security Element via Plasmon Excitation
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Solution Overview
Problem
The production of security elements with complex, high-resolution optical effects is time-consuming and costly due to the technical challenges of achieving fine structures and patterns, particularly in partially demetallized areas, which require precise embossing and metallization processes.
Innovation Solution
A method involving a carrier substrate with different surface structures, where surface plasmon polaritons are excited by electromagnetic radiation to selectively remove a metal layer in specific regions, allowing for precise demetallization without the need for high aspect ratios or complex masking processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high aspect ratio grids are used for demetallization, then selective removal precision is improved, but manufacturing complexity and defect risk increase
Solution Approach 1:
The patent replaces the mechanical embossing process with a chemical etching process. Instead of physically embossing high aspect ratio grids into the substrate and metal layer, the invention uses chemical etchants that selectively remove metal from grid areas based on the light-trap effect, eliminating the need for complex mechanical embossing equipment and reducing process complexity while maintaining demetallization precision
Solution Approach 2:
The patent introduces a chemical etching process as an intermediary step between substrate preparation and final demetallization. The etchant acts as a mediator that selectively removes metal from grid areas without requiring direct mechanical contact or high aspect ratio structures, thereby simplifying the overall manufacturing process while achieving the desired selective demetallization
2Manufacturing precision
If finer grid structures are embossed for higher resolution, then pattern accuracy is improved, but manufacturing speed decreases
Solution Approach 1:
The patent replaces mechanical embossing with chemical etching, which can process finer grid structures more rapidly. The chemical etching process does not suffer from the same speed limitations as mechanical embossing when dealing with fine features, allowing high-resolution patterns to be produced without sacrificing manufacturing speed
Solution Approach 2:
The patent changes the fundamental processing parameter from mechanical deformation (embossing) to chemical dissolution (etching). This parameter change enables the processing of finer grid structures at higher speeds, as chemical etching can uniformly remove material from complex geometries without the mechanical constraints that limit embossing speed
3Ease of manufacture
If high aspect ratio structures are created, then light absorption is improved, but structural stability and quality deteriorate
Solution Approach 1:
The patent replaces mechanical embossing that creates high aspect ratio structures with chemical etching that creates low aspect ratio grid structures. The chemical etching process produces shallower, more stable grid structures that maintain structural integrity and quality while still achieving effective light absorption and demetallization through the chemical reaction
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
Enables the production of security elements with high structural resolution and complexity in a simpler and more efficient manner, facilitating the creation of fine patterns and designs without increasing the risk of defects or reducing manufacturing speed.
Implementation Method 1
removing the metal layer by exciting surface plasmon polaritons by means of electromagnetic radiation in the first region having the first structure
Implementation Method 2
The metal can therefore be removed more easily from these areas, either by laser irradiation or by etching, than from the smooth surfaces
Implementation Method 3
This method is based on the local absorption of light, which is effective-medium theory can be calculated
Data Source
Figure 1a~1b
Figure 2~3a
Figure 3b~3c
AI summary
A method for manufacturing a partially demetallized layer element comprises the steps of: supplying a layer element having a carrier substrate with a face that has at least one first and one second region, wherein the first region has a first structure which is different from a second structure of the second region, and at least one metal layer is arranged on the face of the carrier substrate; and removing the metal layer by exciting surface plasmon polaritons by means of electromagnetic radiation in the first region having the first structure. A layer element and an apparatus for carrying out the method are provided.