Micro-optical System with Fresnel Lenses for Security Authentication
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Solution Overview
Problem
Current security features for authenticating documents and products are thick, require special devices for visual control, and face challenges in mass production due to sensitivity in illumination conditions and ease of counterfeiting.
Innovation Solution
A micro-optical system using off-axis Fresnel lenses with a depth of 0.1 to 0.3 microns, allowing for controllable image motion and reduced thickness, enabling standard mass production and application in various security features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If conventional lenticular lenses with thickness of 10 microns or more are used, then image sharpness can be maintained, but the overall system thickness becomes 30-40 microns which is too thick for practical security applications
Solution Approach 1:
The patent changes the fundamental optical parameter by using Fresnel lenses instead of conventional lenticular lenses. Fresnel lenses achieve the same focusing capability with much thinner profile due to their segmented design that maintains the optical path length while reducing physical thickness to micrometer scale, thus resolving the contradiction between thinness and image quality
Solution Approach 2:
The patent transitions from three-dimensional lenticular lenses to two-dimensional Fresnel lens patterns printed on transparent substrates. This dimensional reduction allows the optical functionality to be achieved in a planar format that can be integrated into thin security features while maintaining image sharpness through precise optical design
2Reliability
If conventional security features requiring special control devices are used, then authentication reliability is improved, but ease of operation deteriorates as consumers cannot perform visual control
Solution Approach 1:
The security feature performs self-authentication through visible image formation and motion effects that can be directly observed by consumers without special devices. The system uses everyday light sources and normal viewing conditions to enable consumers to verify authenticity themselves, eliminating the need for specialized authentication equipment while maintaining reliability
Solution Approach 2:
The patent employs optical effects that produce visible image formation, color changes, and motion effects under normal lighting conditions. These visual phenomena provide clear, easily observable authentication signals that consumers can detect without special devices, thereby improving both reliability and ease of operation
3Manufacturing precision
If thick multi-layer optical systems are used, then image formation capability is improved, but device complexity and difficulty of mass production increase
Solution Approach 1:
The patent merges multiple optical functions into a single integrated layer by printing Fresnel lens patterns directly on transparent substrates. This consolidation eliminates the need for separate lenticular layers, adhesive layers, and precise multi-layer alignment, significantly reducing structural complexity while maintaining image formation capability through the optical design of the Fresnel patterns themselves
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 system provides a robust, easy-to-control image motion effect with enhanced dynamical motion, suitable for mass production and application in security features, protecting against counterfeiting with reduced thickness and expanded usability.
Implementation Method 1
The micro-optical system consists of identical flat nonintersecting optical elements with a saddleshaped phase function, which produce the specified radiation pattern of scattered light
Implementation Method 2
The amplitude of the motion of each image cannot exceed the size of the flat optical element that synthesizes it
Data Source
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AI summary
The micro-optical system of the synthesis of visual images claimed as the invention is primarily a device used to certify the authenticity of products and can be used efficiently to protect bank notes, securities, documents, plastic cards, bank charge cards, documentary, identification, and control stamps, and various consumer goods against counterfeit. The micro-optical system in accordance with the claimed invention consists of a base with a single layer of flat optical elements, which have the form of flat off-axis Fresnel lenses with a paraboloid phase function or flat off-axis Fresnel lenses with a saddle-shaped phase function made in the form of microrelief and effecting, when the microoptical system is illuminated, the synthesis of images consisting of separate points exhibiting the visual effect of the motion of synthesized images when the base is tilted with respect to the observer. The technical result consists in improved reliability of the visual control of the products protected using the claimed system due to the creation of easy-to-control effect of image motion combined with reduced thickness of the claimed system. The invention can be implemented using the already available standard equipment.