Micro Relief Structure for Full Parallax Diffraction Images
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Solution Overview
Problem
Existing diffraction optical variable images can only achieve parallax in one direction under white light illumination, lacking full parallax capabilities and failing to reconstruct images in reflected or transmitted light directions.
Innovation Solution
A micro relief structure is created using a phase plate to achieve full parallax diffraction optical variable images by combining phase calculation methods and optical assembly design, allowing parallax in both horizontal and vertical directions under white light illumination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a diffraction grating structure is used to achieve clear image reconstruction under white light illumination, then chromatic dispersion is strong and image clarity is improved, but parallax in the vertical direction is lost
Solution Approach 1:
The patent transitions from a two-dimensional diffraction grating structure to a three-dimensional micro relief structure with depth modulation. By adding the vertical dimension (depth) to the traditional planar grating, the structure can simultaneously achieve chromatic dispersion for image clarity and vertical parallax effects, resolving the contradiction between image clarity and parallax direction.
Solution Approach 2:
The patent modifies the structural parameters of the diffraction element by introducing variable depth information in the micro relief structure. This parameter change allows the structure to control both the horizontal and vertical light diffraction angles, enabling full parallax effects while maintaining clear image reconstruction under white light illumination.
2Reliability
If a diffraction grating structure is designed for ±1 level light reconstruction, then image reconstruction in specific directions is achieved, but no image is reconstructed in reflected light/transmitted light (0 level) direction
Solution Approach 1:
The patent designs the micro relief structure to perform multiple functions simultaneously: it can reconstruct images in ±1 level directions for oblique viewing and also in the 0 level direction for reflected and transmitted light. This multi-functional design ensures reliable image reconstruction across all light directions, enhancing both reliability and adaptability.
3Ease of manufacture
If existing diffraction optical variable image structures are used, then manufacturing through molding process is achieved, but full parallax diffraction optical variable image cannot be obtained under white light illumination
Solution Approach 1:
The patent pre-calculates and pre-processes the phase information of the micro relief structure using computer algorithms before manufacturing. This preliminary action allows the complex three-dimensional micro relief structure with full parallax capabilities to be designed and optimized in silico, making it feasible to manufacture through conventional molding processes while achieving full parallax diffraction optical variable images.
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 solution enables the reconstruction of dynamic and three-dimensional images with full parallax effects in all directions, enhancing the anti-counterfeiting capabilities and visual appeal of security devices.
Implementation Method 1
The optical structure of these anti-counterfeiting products is diffraction grating of a surface relief type... under the condition of white light illumination, can reconstruct three-dimensional effect, dynamic change, color change images
Implementation Method 2
A method for obtaining a phase of a micro relief structure... by means of combining a phase plate, obtains a micro relief structure
Data Source
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AI summary
The present invention discloses an optical security device with full parallax diffraction optical variable image, the optical security device comprises: a base layer; and an optical assembly at least partially covering a surface of the base layer; wherein the optical assembly has a micro relief structure, so that when a beam of white light illuminates on the optical assembly, the optical assembly presents a full parallax image under the action of the micro relief structure. The present invention obtains the micro relief structure through combining the phase plate, and achieves the reconstruction of the full parallax diffraction optical variable image under the condition of white light illumination.