Security Element Hexagonal Microcavity Structure
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Solution Overview
Problem
Existing security elements for valuable documents, such as banknotes, face limitations in size and manufacturing complexity due to moiré enlargement requirements, which affect the size and detail of microimages, and struggle to provide strong contrast without increasing production effort.
Innovation Solution
A security element featuring a microcavity structure with non-orthogonal, hexagonally arranged microcavities of 0.5 to 3 μm aperture width, coated to produce a color effect, which enhances contrast and resolution by varying brightness and diffractive properties based on viewing direction, allowing for high-resolution motifs without complex printing processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If microcavities are arranged in a regular orthogonal grid pattern, then manufacturing is simplified, but the contrast and resolution of microimages deteriorate
Solution Approach 1:
The patent applies asymmetry by transitioning from a conventional orthogonal grid arrangement to a hexagonal arrangement of microcavities. This asymmetric change in geometric pattern enhances the optical properties and contrast of microimages while maintaining manufacturability through standard embossing techniques.
Solution Approach 2:
The patent changes the geometric parameter of the microcavity arrangement from orthogonal to hexagonal. This parameter change in the spatial configuration improves the optical performance and image resolution without compromising the ease of manufacturing, as hexagonal patterns can still be produced using conventional embossing methods.
2Manufacturing precision
If microcavity aperture size is increased, then manufacturing precision improves, but the area available for high-resolution motifs decreases
Solution Approach 1:
The patent resolves the contradiction by optimizing the depth dimension of microcavities while maintaining small aperture widths. By varying the depth (z-dimension) rather than increasing aperture size, the patent achieves high manufacturing precision and strong optical contrast without sacrificing the lateral area available for microimage motifs.
Solution Approach 2:
The patent applies local quality by creating variations in microcavity depth across different regions to form images. Different depths provide different optical properties (reflective vs. non-reflective), enabling high-resolution imaging with small apertures while maintaining sufficient lateral area for motifs.
3Manufacturing precision
If complex printing processes are used to achieve strong contrast, then microimage quality improves, but production complexity increases
Solution Approach 1:
The patent replaces complex printing processes with a mechanical embossing system that creates three-dimensional microcavity structures. This substitution achieves strong contrast through optical effects from the 3D geometry rather than through complex multi-step printing, thereby simplifying the production process while maintaining high image quality.
Solution Approach 2:
The patent changes the approach from two-dimensional printing to three-dimensional structuring. By varying the depth parameter of microcavities, the patent achieves strong contrast and high-quality images using a single embossing step rather than complex printing processes.
4Illumination intensity
If microcavity depth is increased, then optical contrast improves, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies partial action by using moderate depth variations rather than uniformly deep microcavities. By optimizing depth to provide sufficient optical contrast without excessive depth, the patent achieves good contrast while maintaining reasonable manufacturing precision requirements within the 0.5-3 μm aperture range.
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
The solution provides strong contrast and high-resolution microimages that are difficult to reproduce, even without magnification, while simplifying production and maintaining optical effectiveness across various viewing angles, thus enhancing security against forgery.
Implementation Method 1
a microcavity structure being provided which has a plurality of microcavities lying next to one another in a regular pattern, wherein the microcavities each have an aperture width of 0.5 μm to 3 μm when viewed in a spatial direction parallel to the top, a coating that produces a color effect is provided over the microcavity structure
Implementation Method 2
The microcavities have an aperture size between 0.5 μm and 3 μm along the top and are optically reflective or highly refractive on their surface, so that at least partial reflection takes place on the surface
Implementation Method 3
a coating that produces a color effect is provided over the microcavity structure
Data Source
Figure 1~2
Figure 3
Figure 4~6
AI summary
The invention relates to a security element for the production of valuable documents, such as banknotes, checks or the like, which has a top surface that provides a micro-image (12), wherein a microcavity structure (1) is provided which has a plurality of adjacent microcavities (3) arranged in a regular pattern (14), wherein the microcavities (3) each have an aperture width of 0.5 µm to 3 µm when viewed in a spatial direction parallel to the top surface, and a coating (15; 19.1, 19.2) producing a color effect is provided over the microcavity structure (1), wherein the pattern (14) of the microcavities (3) in a top view has the form of a non-orthogonal, two-dimensional grid type.