Optical Security Component with Segmented Diffraction Gratings
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Solution Overview
Problem
Existing optical security components are sensitive to observation conditions and lack visibility in ambient lighting, making them vulnerable to counterfeiting and difficult to authenticate without a polarizer, as they rely on specific orientations and polarized light for distinct configurations.
Innovation Solution
An optical security component featuring a film with at least two diffracting networks of distinct orientations, each with a period less than 550 nm and modulation between 0.25 and 0.5, integrated with a diffusing treatment and a reflective layer, allowing for visible configurations under polarized and non-polarized light, and encapsulated between layers of different optical indices for enhanced visibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a polarizer is used to observe the optical component, then distinct configurations with inverted contrast are visible, but the component becomes sensitive to observation conditions and requires specialized tools for authentication
Solution Approach 1:
The optical component is divided into multiple surface elements with different vector orientations (parallel and perpendicular arrangements of g(x,y) and r(x,y) structures). Each element responds differently to polarized light, creating distinct visual configurations that can be observed with or without a polarizer, thereby reducing dependency on specialized observation equipment while maintaining authentication accuracy.
Solution Approach 2:
The component utilizes optical effects that produce visible contrast changes and configuration differences under polarized versus non-polarized light. The surface elements display differentiated visual characteristics (light/dark configurations) that enable authentication without requiring polarized light, thus reducing device complexity while preserving measurement precision.
2Reliability
If high frequency structures are used to improve security, then counterfeiting becomes more difficult, but the structures become invisible in ambient lighting without a polarizer
Solution Approach 1:
The high frequency relief structure is segmented into different surface elements with varying vector orientations relative to the low frequency structure. This segmentation allows certain elements to remain visible in ambient light while others provide polarized light authentication, thereby maintaining both counterfeit resistance and ambient visibility.
Solution Approach 2:
Different regions of the optical component have different optical properties: some surface elements are designed to be visible in ambient light for general identification, while others are optimized for polarized light observation to provide security authentication. This local differentiation ensures both ease of operation and reliability.
3Ease of operation
If the optical component is designed to be visible in ambient light, then authentication can be performed without specialized tools, but the structure becomes more sensitive to observation conditions
Solution Approach 1:
The component is segmented into surface elements with different vector configurations that provide multiple levels of visibility. Some elements are optimized for ambient light observation to enable easy authentication without polarizers, while others provide polarized light responses for enhanced security. This segmentation reduces sensitivity to observation conditions by ensuring functionality across different lighting scenarios.
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 robust, polarizer-independent visibility in ambient light, reducing sensitivity to observation conditions and enabling immediate visual authentication without specialized tools, while maintaining security through polarized effects.
Implementation Method 1
a film stamped to form at least two diffracting networks with distinct orientations
Implementation Method 2
The component also comprising a diffusing treatment
Implementation Method 3
integrated with a diffusing treatment and a reflective layer
Data Source
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AI summary
The present invention relates to an optical security marking component producing a first visible configuration when observed through a polarizer oriented in a first orientation, and a second configuration, separate from the first, visible when observed through the polarizer oriented in a second orientation, the optical component comprising a stamped film for forming at least two diffraction gratings having different orientations, characterized in that each of said gratings has a period of less than 550 nm and a modulation between 0.25 and 0.5 relative to a reference plane.