Optically Variable Security Element Encoding Multiple Motifs
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Solution Overview
Problem
Conventional optically variable security elements primarily produce reflection images and struggle to encode multiple motifs due to the need for large angular ranges to separate images, limiting the number of motifs that can be encoded.
Innovation Solution
An optically variable security element with a relief layer featuring structurally identical individual optical elements, each divided into sub-surfaces with different specular reflectivities, and interwoven with a diffraction grating structure, allowing for viewing-angle-dependent reflection and diffraction motifs that form intertwined images visible to the naked eye.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If conventional optically variable security elements use only reflective structures, then the manufacturing process is simple, but the information density and security are limited
Solution Approach 1:
The patent combines two different optical principles (reflection and diffraction) into a single security element. The relief layer with directionally reflective elements and the diffraction grating layer work together to encode multiple motifs, thereby increasing information density without proportionally increasing manufacturing complexity
Solution Approach 2:
The security element uses a composite structure with different functional layers: a relief layer for reflection and a diffraction grating layer for diffraction. This composite approach allows multiple optical effects to coexist, enabling higher information density while maintaining a systematic manufacturing process
2Loss of information
If multiple motifs are encoded in conventional security elements, then information density increases, but large angular ranges are required to separate images
Solution Approach 1:
The security element divides the encoded information into separate motifs that can be selectively accessed. The relief layer encodes first motifs and the diffraction grating layer encodes second motifs, allowing multiple distinct patterns to be packed into a compact area without requiring large angular separation ranges
Solution Approach 2:
The patent adds a vertical dimension by stacking two functional layers (relief layer and diffraction grating layer). This layered approach allows multiple motifs to be encoded in the same planar area by using different optical paths, thereby increasing information density without requiring larger angular ranges
3Loss of information
If diffraction grating structure is added to increase information density, then manufacturing complexity increases, but the patent claims simplified production
Solution Approach 1:
The diffraction grating structure is pre-formed in the planar areas between the relief structure elements. This preliminary arrangement allows the diffraction grating to be integrated into the manufacturing process without requiring complex post-processing or alignment steps, thereby maintaining ease of manufacture while increasing information density
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 encoding of multiple reflection and diffraction motifs without the need for shading, allowing for a higher density of information and improved visibility from various angles, enhancing security and readability.
Implementation Method 1
Each element has a surface that is divided into sub-surfaces exhibiting different directional reflectances. These sub-surfaces are grouped such that each group comprises a sub-surface of an element surface, and each group of sub-surfaces encodes a corresponding viewing-angle-dependent, naked-eye reflection pattern.
Implementation Method 2
at least one planar area is provided in the relief layer, which extends between the individual optical elements and is equipped with a diffraction grating structure applied over the at least one planar area, which, through the specified directed illumination, generates viewing angle-dependent diffraction patterns that are visible to the naked eye.
Implementation Method 3
The viewing-angle-dependent diffraction patterns and the viewing-angle-dependent reflection patterns form overall images that are also visible to the naked eye. The diffraction patterns and reflection patterns are interlocked.
Data Source
Figure 1a~1b
Figure 2
Figure 3~4
AI summary
The invention relates to an optically variable security element (1) comprising a relief layer (102) having a plurality of structurally identical optical individual elements (2) which each have an individual element surface (6) which is divided into part-surfaces (61, 62) which have different directed degrees of reflection, and the part-surfaces (61, 62) are divided into groups in such a way that each group comprises a part-surface (61, 62) of an individual element surface (6) and each group encodes an associated reflection motif which is dependent upon the viewing angle and is visible with the naked eye, also comprising at least one planar region (3) which extends between the optical individual elements (2) and comprises part-regions (31, 32) having diffraction gratings, which by the predetermined directed light produce at least one diffraction motif which is dependent upon the viewing angle and is visible with the naked eye, and the reflection motifs dependent upon the viewing angle and the at least one diffraction motif dependent upon the viewing angle produce total motifs which are visible with the naked eye.