Security Element Moiré Magnification Design Freedom
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Solution Overview
Problem
Conventional security elements with moiré magnification arrangements are limited in design flexibility and thickness, as motif elements must fit within a lattice cell, restricting the creation of larger, non-overlapping moiré image elements and preventing the production of thinner magnification arrangements.
Innovation Solution
A microoptical moiré-type magnification arrangement that allows motif image elements to be distributed across multiple lattice cells, enabling the creation of larger, non-overlapping moiré image elements and thinner designs by using a focusing element grid with a periodic or locally periodic arrangement of microfocusing elements, which can be larger than a single lattice cell, and employing Bravais lattices with low symmetry for enhanced security and design freedom.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If motif elements are constrained to fit within a single lattice cell, then the manufacturing and alignment process is simplified, but the design freedom and size of moiré image elements are restricted
Solution Approach 1:
The motif image is divided into multiple lattice cells, with each lattice cell containing a portion of the motif image. Multiple spaced-apart lattice cells collectively form complete micromotif elements, allowing the motif to extend across lattice cell boundaries while maintaining manufacturing simplicity through the periodic lattice structure.
2Adaptability or versatility
If motif elements are distributed across multiple lattice cells, then larger and more complex moiré image elements can be created, but the alignment precision requirements increase
Solution Approach 1:
The patent employs Bravais lattices with low symmetry (such as rectangular, centered rectangular, or rhombic lattices) rather than high-symmetry lattices. This low-symmetry arrangement enhances security by making the pattern harder to replicate while still maintaining precise alignment through the periodic structure. The asymmetric lattice cells distribute motif portions in a way that requires precise registration but enables complex motif designs.
3Length of stationary object
If the magnification arrangement is made thinner, then the security element becomes more compact and less intrusive, but the focal length and optical performance are compromised
Solution Approach 1:
The patent changes the periodicity parameters of the lattice arrangement to optimize the balance between thickness and optical performance. By carefully selecting the lattice periodicity and the spacing between lattice cells, the design achieves a thin profile while maintaining sufficient focal length for effective moiré magnification. The periodicity is chosen to be between 3 μm and 50 μm, optimizing both compactness and optical function.
4Ease of manufacture
If high-symmetry lattices are used, then the manufacturing process is more straightforward, but the security against unauthorized reproduction is reduced
Solution Approach 1:
The patent explicitly employs Bravais lattices with low symmetry, including rectangular lattices, centered rectangular lattices, and rhombic lattices. These low-symmetry arrangements are inherently more difficult to replicate accurately and provide enhanced security features. The asymmetric lattice structure creates unique diffraction and moiré patterns that are harder to counterfeit compared to high-symmetry lattices, while still allowing for straightforward manufacturing through standard lithographic techniques.
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 approach provides greater design freedom for moiré motifs, allows for expansive and thin moiré image elements, and enhances security by making it difficult to replicate the low-symmetry arrangement, thereby improving the authenticity verification and protection against unauthorized reproduction of security documents.
Implementation Method 1
a microoptical moiré-type magnification arrangement for depicting a moiré image having one or more moiré image elements
Implementation Method 2
a focusing element grid that is arranged spaced apart from the motif image and that includes a periodic or at least locally periodic arrangement of a plurality of lattice cells having one microfocusing element each
Data Source
AI summary
The present invention relates to a security element (16) for security papers, value documents and the like, having a microoptical moiré-type magnification arrangement for depicting a moiré image (84) having one or more moiré image elements (86), havinga motif image that includes a periodic or at least locally periodic arrangement of a plurality of lattice cells (24) having micromotif image portions (28, 28′, 28″),for the moiré-magnified viewing of the motif image, a focusing element grid (22) that is arranged spaced apart from the motif image and that includes a periodic or at least locally periodic arrangement of a plurality of lattice cells having one microfocusing element (22) each,wherein, taken together, the micromotif image portions (28, 28′, 28″) of multiple spaced-apart lattice cells (24) of the motif image each form one micromotif element (50) that corresponds to one of the moiré image elements (86) of the magnified moiré image (84) and whose dimension is larger than one lattice cell (24) of the motif image.