Optical Device Triangular Lattice Diffractive Forgery Prevention
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Solution Overview
Problem
Current optical devices using holograms or diffraction gratings for forgery prevention lack a unique visual effect that can distinguish genuine from non-genuine articles effectively, as they often emit diffracted light in both positive and negative angular ranges with similar visibility, making it difficult to discriminate between the two.
Innovation Solution
An optical device comprising a particulate layer of transparent particles arranged in a specific triangular lattice structure with a reflecting layer and a carrier layer, where the average center-to-center distance of the particles is set sufficiently small to emit diffracted light with high visibility only in negative angular ranges, achieving a dark muddy color in other conditions, and utilizing a polarizer to alternate between bright and dark images based on illumination direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional holograms or diffraction gratings are used, then the optical device can display diffracted light, but the visual effect is not unique and cannot effectively distinguish genuine from non-genuine articles
Solution Approach 1:
The patent applies local quality by creating a specific triangular lattice structure of transparent particles with precise spacing (average center-to-center distance of 1-10 μm) that produces unique optical properties. This localized structural arrangement causes the device to emit diffracted light only in negative angular ranges under specific illumination conditions, providing a unique visual effect for authentication while maintaining relatively simple device structure.
2Measurement precision
If the particulate layer uses transparent particles arranged in a triangular lattice with small center-to-center distance, then diffracted light is emitted with high visibility only in negative angular ranges, but the device becomes more complex to manufacture
Solution Approach 1:
The patent applies parameter changes by optimizing the average center-to-center distance of transparent particles within a specific range (1-10 μm) and controlling the triangular lattice structure to achieve the desired optical effect. By adjusting these parameters, the device emits diffracted light with high visibility only in negative angular ranges. The patent also specifies that particle diameter should be 0.5-5 times the center-to-center distance, providing manufacturing guidelines while achieving precise angular control.
3Ease of manufacture
If the optical device emits diffracted light in both positive and negative angular ranges with similar visibility, then the device is simpler to manufacture, but it is difficult to discriminate between genuine and non-genuine articles
Solution Approach 1:
The patent applies asymmetry by designing the triangular lattice structure with specific orientation and spacing that creates asymmetric diffraction patterns. The transparent particles are arranged in a triangular lattice with average center-to-center distance of 1-10 μm, which produces asymmetric light distribution - emitting diffracted light with high visibility only in negative angular ranges while suppressing positive angular range emission. This asymmetric optical characteristic provides reliable discrimination between genuine and non-genuine articles.
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 optical device achieves superior forgery prevention by emitting diffracted light with high visibility only under specific conditions, displaying a dark muddy color in normal observation and spectral colors in negative angular ranges, making it difficult to replicate and thus enhancing authentication.
Implementation Method 1
the average center-to-center distance of the particles is set sufficiently small to emit diffracted light with high visibility only in negative angular ranges
Implementation Method 2
a reflecting layer and a carrier layer, where the average center-to-center distance of the particles is set sufficiently small to emit diffracted light with high visibility only in negative angular ranges
Data Source
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AI summary
A special visual effect is achieved. An optical device (1) includes a light-reflecting interface provided with a first relief structure including first recesses or protrusions arranged two-dimensionally, the first relief structure emitting a first diffracted light when illuminated with a light, and a light-transmitting interface disposed in front of the light-reflecting interface and having a reflectance smaller than that of the first interface, the light-transmitting interface being provided with a second relief structure including second recesses or protrusions arranged two-dimensionally, and the second relief structure emitting a second diffracted light when illuminated with the light.