Optically Variable Security Element Encoding
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Solution Overview
Problem
Conventional optically variable security elements with relief structures face challenges such as complex and expensive production, high relief structure requirements, and limited ability to encode multiple motifs, leading to inefficiencies in angular dependence and visibility of images.
Innovation Solution
A method involving a relief layer with individual optical elements and an information layer directly adjacent to the relief layer, where the relief layer is metallized and the information layer is formed by demetallizing reflection areas with laser lithography, allowing for directional reflectance to encode motifs that change with viewing angle without shading, enabling multiple motifs to be encoded and visible from specific positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional relief structures are used to achieve angle-dependent optical effects, then the optical visibility is improved, but the production complexity and cost increase
Solution Approach 1:
The patent divides the information layer into multiple sub-motifs that are spatially separated and assigned to different viewing angles. Each sub-motif is encoded on a specific relief structure, allowing the overall image to be segmented into angle-dependent components. This segmentation enables complex optical effects to be achieved through simpler, modular production steps rather than requiring a single complex relief structure.
Solution Approach 2:
The patent applies different properties to different regions of the information layer. Specifically, different sub-motifs are assigned different spatial frequencies, orientations, and positional relationships relative to the relief structures. This local differentiation allows each region to contribute to specific viewing angles, improving optical visibility while simplifying the overall production process by treating each region independently.
2Adaptability or versatility
If high relief structures are used to encode multiple motifs, then the angular dependence is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The patent transitions from encoding multiple motifs through vertical relief height variations to encoding them through horizontal spatial distribution and angular positioning. By utilizing the angular dimension and spatial frequency domain, the patent can encode multiple motifs with low relief heights, thereby reducing manufacturing precision requirements while maintaining the ability to display multiple motifs from different angles.
Solution Approach 2:
The patent changes the encoding parameters from relying on relief height to utilizing spatial frequency, orientation, and angular position. By varying these parameters across different sub-motifs, the patent achieves multiple motif encoding with consistent, low relief heights, significantly reducing the manufacturing precision required compared to traditional high-relief approaches.
3Loss of information
If multiple motifs are encoded on the same element, then the information density is improved, but the visibility from specific angles decreases due to shading
Solution Approach 1:
The patent segments the multiple motifs into spatially separated sub-motifs, each assigned to a specific angular range. By distributing the information across different angular zones rather than overlapping them, the patent achieves high information density without the shading problems that occur when multiple motifs share the same physical space. Each sub-motif remains clearly visible from its designated viewing angle.
Solution Approach 2:
The patent resolves the visibility conflict by utilizing the angular dimension as an additional encoding space. Instead of competing for the same two-dimensional physical space, multiple motifs are distributed across different angular positions and spatial frequencies. This dimensional expansion allows all motifs to be simultaneously encoded with high visibility, as each is optimized for its specific angular range without interfering with others.
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 reduces production complexity, allows for low relief heights, and enhances the visibility of encoded motifs by leveraging directional reflectance, enabling multiple motifs to be perceived from different angles without shading issues, thus improving the efficiency and effectiveness of optically variable security elements.
Implementation Method 1
the relief layer is metallized and the information layer is formed by demetallizing reflection areas with laser lithography, allowing for directional reflectance to encode motifs that change with viewing angle
Implementation Method 2
the information layer is formed by demetallizing reflection areas with laser lithography
Data Source
Figure 1a~1b
Figure 2
Figure 3a~3f
AI summary
The invention relates to a method for manufacturing a visually variable security element (20) by breaking down a first motif (F) into first motif elements (91, 92, 93, 94, 95), assigning the first motif elements (91, 92, 93, 94, 95) first directional degrees of reflection that encode the first motif (F), a relief layer (50) having a multiplicity of single visual elements (51, 52, 53, 54, 55, 110, 111, 112, 113, 114) having a respective single element surface (3) is produced, the single element surface (3) is divided into reflection areas (61–80), first reflection areas (61-65) of different single element surfaces (3) are assigned to the first motif (F), the first reflection areas (61–65) associated with the first motif (F) are provided with the first directional degrees of reflection.