Optical Security Device with Grayscale In-Plane Image and Control Patterns
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Solution Overview
Problem
Micro-optic security systems with embedded lens arrays suffer from ghost images and increased sensitivity to manufacturing variations, making them unsuitable for sealed lens formats due to high f-numbers and blurriness.
Innovation Solution
An optical security device featuring a grayscale in-plane image with intermingled control patterns of icons, where the array of icon focusing elements forms synthetically magnified images with dynamic effects, ensuring the image remains 'on' and resistant to manufacturing variations by choreographing optical effects across different angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a sealed lens format with embedded lens array is used, then the device structure is compact and integrated, but ghost images appear and manufacturing sensitivity increases
Solution Approach 1:
The patent extracts the problematic sealed lens format and replaces it with an open lens configuration where the lens array is positioned adjacent to the micro-optic film material rather than embedding it. This separation removes the source of ghost images while maintaining the functional integration of the optical components.
Solution Approach 2:
The patent changes the f-number parameter from high (around 2) to low (around 0.95) by adjusting the lens geometry and aperture. This parameter change reduces the system's sensitivity to manufacturing variations and eliminates ghost images while maintaining compact form factor.
2Device complexity
If high f-number is used in sealed lens format, then the lens structure is simpler, but blurriness increases and manufacturing sensitivity increases
Solution Approach 1:
The patent changes the f-number parameter from high (around 2) to low (around 0.95) by adjusting the lens geometry and aperture. This parameter change reduces the system's sensitivity to manufacturing variations and eliminates ghost images while maintaining compact form factor.
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 enhanced design capability, improved visual impact, and reduced sensitivity to manufacturing variations, ensuring the synthetic images remain clear and dynamic across different viewing angles without ghost images, making it suitable for various applications like banknotes and passports.
Implementation Method 1
an array of icon focusing elements positioned to form at least one synthetically magnified image of at least a portion of the icons in each coextensive control pattern of icons
Data Source
AI summary
An improved form of optical security device for use in the protection of documents and articles of value from counterfeit and to verify authenticity is provided. The inventive device, which is made up of an optionally embedded array of icon focusing elements, at least one grayscale in-plane image, and a plurality of coextensive control patterns of icons contained on or within the in-plane image, each control pattern being mapped to areas of the grayscale in-plane image having a range of grayscale levels, provides enhanced design capability, improved visual impact, and greater resistance to manufacturing variations.