Faceted Diffractive Optical Security Components for Dynamic Tilt Effects
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Solution Overview
Problem
Existing optical security components relying on Moiré effects are limited by the size of the micro-image and require specialized equipment for high resolution, and they do not provide dynamic visual effects when tilted in certain directions.
Innovation Solution
An optical security component with a structure of facets arranged in subsets, allowing dynamic visual effects through tilt and azimuth movements, without relying on Moiré effects, achieved by structuring a single layer with facets of varying heights and slopes, and optionally combined with a subwavelength diffraction grating for additional effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If Moiré effects are used in optical security components, then dynamic visual effects can be achieved, but the micro-image size is limited and high resolution requires specialized equipment
Solution Approach 1:
The patent replaces the Moiré effect mechanism with a direct diffractive optical structure. Instead of using two overlapping periodic patterns to create Moiré fringes, the invention uses a single diffractive structure with controlled phase delays to directly generate the desired optical effects, eliminating the need for specialized high-resolution equipment
Solution Approach 2:
The patent changes the fundamental optical parameter from Moiré interference patterns to diffractive phase modulation. By controlling the phase delay introduced by the diffractive structure, the system achieves dynamic visual effects without the size and resolution constraints of Moiré-based approaches
2Adaptability or versatility
If Moiré effects are used for dynamic visual effects, then movement can be observed, but no dynamic effect is produced when tilted in certain directions
Solution Approach 1:
The patent employs asymmetric diffractive structures with specific orientation relationships between orthogonal grating sets. This asymmetry in the diffractive element design enables the structure to produce dynamic visual effects in all tilt directions, overcoming the directional limitations of symmetric Moiré-based systems
Solution Approach 2:
The patent creates dynamically responsive optical effects that adapt to viewing angle in all directions. The diffractive structure is designed to produce different visual effects depending on the tilt direction and magnitude, providing continuous dynamic feedback regardless of the orientation of the security component
3Manufacturing precision
If micro-images are engraved in microlenses for Moiré effect, then dynamic effects can be achieved, but the size is constrained to the order of the microlens size
Solution Approach 1:
The patent transitions from two-dimensional micro-image engraving within microlens constraints to a diffractive structure that operates in the angular dimension. By encoding information in the phase and orientation of diffractive gratings rather than in spatial micro-images, the system achieves high resolution without being constrained by microlens size
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 component provides complex, high-resolution dynamic visual effects observable with the naked eye or imaging devices, enhancing security and authentication without the size constraints of Moiré-based systems, and offering flexibility in design and manufacturing.
Implementation Method 1
The structure has a first pattern comprising a bas-relief with a first set of facets... modulated by a second pattern forming a sub-wavelength grating
Implementation Method 2
An optical security component with a visible effect in reflection
Implementation Method 3
a first pattern comprising a bas-relief with a first set of facets... modulated by a second pattern forming a sub-wavelength grating
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3A~3B
AI summary
The invention notably relates to an optical security component (201) comprising a first layer (213), at least a diffractive first structure (S) etched into the first layer, a reflective second layer (214) at least partially covering the diffractive first structure. The diffractive first structure comprises a first pattern (M1) made up of a collection of facets arranged in such a way as to form a plurality of subsets of facets, each subset of facets comprising one or more facets with symmetry of revolution which are arranged concentrically. Within each group of a plurality of groups of subsets of facets, the subsets of facets exhibit, at discrete regions defined by identical polar coordinates, a local alteration to the surface such as to produce a graphic object that is recognizable for a given angle of tilt and a given azimuth angle. The polar coordinates vary from one group to another so as to produce a dynamic visual effect that can be seen in reflection by changing the tilt and/or the azimuth.