Diffractive Micro-Optical System for Thin Security Features
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Solution Overview
Problem
Current visual security features for authenticating bank notes, securities, and consumer goods are complex and require skilled expertise, and existing micro-optical systems like 'Motion' are thick and have a limited range of kinematic effects, making them unsuitable for widespread use.
Innovation Solution
A single-layer diffractive micro-optical system with a microrelief depth of less than a micron, utilizing multigrade kinoforms and diffraction gratings with varying orientations and periods, to create kinematic effects of motion in visual images, allowing for easy visual authentication and counterfeiting protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If refractory microlenses are used to form visual images, then the security feature provides kinematic effects of motion, but the thickness of the optical element becomes large
Solution Approach 1:
The patent replaces the mechanical refractory microlens system with a diffractive optical element that uses light diffraction to achieve the same image formation and kinematic effects. This substitution eliminates the need for thick lens structures while maintaining the security functionality through phase modulation of light waves.
Solution Approach 2:
The patent changes the fundamental optical parameter from refraction (microlenses) to diffraction (periodic structures), enabling thin-film implementation. By using diffraction gratings with specific periods and orientations, the system achieves image formation and motion effects in a planar, sub-micron thickness configuration.
2Reliability
If refractory microlenses are used to form visual images, then the security feature provides kinematic effects of motion, but the manufacturing complexity increases
Solution Approach 1:
The patent replaces complex microlens fabrication with diffractive grating patterns that can be manufactured using standard photolithography and etching processes. This substitution dramatically simplifies manufacturing while maintaining optical functionality through wave diffraction rather than mechanical lens curvature.
Solution Approach 2:
The patent transitions from manufacturing three-dimensional lens surfaces to creating two-dimensional periodic patterns with controlled pitch and orientation. This parameter change enables compatibility with planar semiconductor manufacturing processes, reducing complexity while achieving the desired optical effects.
3Ease of operation
If a conventional micro-optical system is used, then visual images are formed, but the range of kinematic effects of motion is limited
Solution Approach 1:
The patent segments the diffractive optical element into multiple zones with different grating periods and orientations, each zone contributing to different aspects of the kinematic effect. This segmentation enables independent optimization of various motion parameters, expanding the overall range of achievable kinematic effects for enhanced security verification.
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 provides a thin, easy-to-authenticate visual security feature with an expanded range of kinematic effects, suitable for various applications, including bank notes and consumer goods, and is protected against counterfeiting due to its unique production technology.
Implementation Method 1
A single-layer diffractive micro-optical system with a microrelief depth of less than a micron, utilizing multigrade kinoforms and diffraction gratings with varying orientations and periods, to create kinematic effects of motion in visual images
Data Source
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AI summary
The claimed micro-optic system for visually verifying the authenticity of an article relates to the field of optical security technologies, and primarily to means, i.e. security marks, which can be used to authenticate banknotes, plastic cards, security papers,etc. In accordance with the claims, a micro-optic system is described for forming the effect of the movement of fragments of an image when a planar optical element is tilted. Grayscale kinoforms are used to form images consisting of several symbols. The kinematic effects of movement consist in the radial movement or rotation of the symbols formed by the kinoforms when an optical element is tilted. Electron-beam technology is used to produce a micro-relief. The claimed micro-optic system can be reproduced using standard security hologram production equipment. The visual kinematic effects are easy to verify. The technical result consists in rendering the visual verification of protected articles more reliable by means of an easily verifiable effect of the movement of an image, and in reducing the thickness of the claimed system. The claimed micro-optic system is well protected against forgeries and imitations. The invention can be carried out using existing standard equipment.