Optical Identifier With Dual-Mode Diffraction Verification
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Solution Overview
Problem
Existing anti-counterfeiting technologies for variable color and stereoscopic displays have poor anti-counterfeiting effects and lack sufficient distinguishing properties.
Innovation Solution
An optical identifier is designed with deflection cells and spatial phase modulators, featuring a relief structure and diffraction gratings, which display a variable color image under diffused light and a reproduced image under a point light source, allowing for two-step verification and enhanced security.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional diffraction grating displays are used for anti-counterfeiting, then variable color images can be displayed, but the anti-counterfeiting effect is poor and easily counterfeited
Solution Approach 1:
The optical identifier is divided into two distinct functional layers: a first optical element layer containing diffraction gratings for variable color display, and a second optical element layer containing spatial phase modulators for reproduced image display. This segmentation allows each layer to perform its specific function independently, creating a multi-step verification system that is difficult to counterfeit while maintaining the variable color display capability.
2Reliability
If stereoscopic display techniques are used, then three-dimensional color images can be displayed, but the technology is already known and lacks sufficient distinguishing properties
Solution Approach 1:
The invention merges two distinct optical display technologies into a single optical identifier: the diffraction grating-based variable color display and the spatial phase modulator-based reproduced image display. By combining these technologies in a multi-layer structure, the invention creates a system with enhanced distinguishing properties that goes beyond conventional stereoscopic displays, while managing technical complexity through functional integration.
3Illumination intensity
If combination of diffraction grating and computer hologram is used, then complicated patterns can be switched with good visibility, but the effect is poor in terms of displaying a color image
Solution Approach 1:
The invention applies local quality by assigning different functional characteristics to different layers of the optical identifier. The first layer (diffraction gratings) is optimized for variable color display with specific spatial frequencies corresponding to R, G, and B colors, while the second layer (spatial phase modulators) is optimized for high-visibility reproduced image display. Each layer has locally optimized properties that address the specific limitations of the other approach.
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 identifier provides a high anti-counterfeiting effect and distinguishability by displaying a brilliant variable color image under diffused light and a clear reproduced image under a point light source, making it difficult to counterfeit and ensuring confidentiality of the reproduced image.
Implementation Method 1
light incident on a diffraction grating is dispersed according to the spatial frequency of the diffraction grating
Implementation Method 2
a display that provides a variable color image uses the fact that, as described in WO2017/183718, light incident on a diffraction grating is dispersed according to the spatial frequency of the diffraction grating
Implementation Method 3
The spatial phase modulator modulates a phase of light outputted from a point light source and displays a reproduced image
Implementation Method 4
The deflection cells diffract diffused light and deflect the diffused light by directional scattering
Data Source
AI summary
An optical identifier including a recording surface, a plurality of deflection cells each of which has recorded thereon a range in which light to be diffracted is deflected, at least one spatial phase modulator which fills a space between the deflection cells on the recording surface, and a deposition layer which covers part or all of the recording surface. The deflection cells has a spatial frequency expressed in a form of a relief structure and are discretely formed on the recording surface at regular intervals away from each other. A variable color image is recorded by pixels defined by the deflection cells. The spatial phase modulator has thereon a distribution of phase differences recorded in a form of heights of the relief structure. The spatial phase modulator modulates a phase of light outputted from a point light source and displays a reproduced image.