Optically Variable Security Element Facet Arrangement
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Solution Overview
Problem
Existing optically variable security elements, such as holograms and microlens structures, face challenges in brilliance, recognizability, and ease of reproduction, with micromirror arrangements often experiencing diffractive effects and requiring large numbers of mirrors for aperiodic configurations, which can reduce brilliance and increase production complexity.
Innovation Solution
A security element with a reflective surface area featuring facets oriented in the same direction, arranged along their common inclination with decreasing length and height, avoiding periodicity and diffractive effects, thus enhancing brightness, brilliance, and security against forgery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If periodic arrangements of micromirrors are used, then manufacturing is simplified, but diffractive effects and colored light reflections occur which disrupt the desired achromatic appearance
Solution Approach 1:
The patent applies aperiodic arrangement of micromirrors with varying slopes and positions to eliminate periodicity. This asymmetric configuration prevents the formation of regular diffraction patterns, thereby eliminating colored light reflections and maintaining an achromatic appearance while still being manufacturable through standard lithographic processes
2Object-generated harmful factors
If aperiodic arrangements of micromirrors are used, then diffractive effects are avoided, but a larger number of micromirrors are required which reduces brilliance
Solution Approach 1:
The patent varies the local properties of micromirror arrangements across different regions. By optimizing the slope, position, and density of micromirrors in specific areas, the design achieves aperiodic configuration that avoids diffraction while maintaining high brilliance through strategic local optimization rather than uniform distribution
3Illumination intensity
If microlens structures are used, then good visibility is achieved, but large layer thickness is required and production is technically challenging
Solution Approach 1:
The patent replaces the microlens structure (optical system based on refraction) with a micromirror arrangement (optical system based on reflection). This substitution achieves the desired visibility and optical variability through reflective surfaces with controlled slopes, eliminating the need for thick lens layers and complex multi-layer production processes while maintaining security against counterfeiting
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 configuration achieves high brightness and brilliance while minimizing diffractive effects and shading, providing a high level of security against reproduction due to its non-periodic arrangement, requiring fewer facets to cover a given area and maintaining a smooth, attractive visual appearance.
Implementation Method 1
a carrier having a reflective surface area containing a plurality of reflective sub-areas, each sub-area having several reflective facets oriented in the same direction
Data Source
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AI summary
The invention relates to an optically variable security element (12) for securing valuable objects, having a substrate (22) with a reflective area (20), the extent of which defines an x-y plane and a z axis perpendicular thereto, wherein the reflective area (20) contains a plurality of reflective portions (30), and each portion (30) has multiple identically oriented reflective facets (32), and an orientation of each facet (32) relative to the x-y plane is defined by indicating its normalised normal vector (n). The projection of the normal vector into the x-y plane defines an inclination direction (r) of the facet. The length (L) of a facet is its dimension in the inclination direction; the width (B) of a facet is its dimension perpendicular to the inclination direction in the x-y plane, and the height (H) of a facet is its dimension in the z direction. According to the invention, the identically oriented facets (32) in the reflective portions (30) are arranged with decreasing length (L) and decreasing height (H) in their common inclination direction (r).