Dual-Direction Laser Security Feature for Value Documents
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Solution Overview
Problem
Existing security features on value documents, such as passports and banknotes, face challenges in ensuring 100% certainty in image verification due to unclear transitions between optically variable effects, which complicates authentication and counterfeit protection.
Innovation Solution
A security feature that combines a positive and an image-processed positive representation using laser-sensitive recording layers with light-diffracting or light-refracting structures, where one is introduced from a first direction and the other from a second direction, allowing for angle-dependent and angle-independent markings, enhancing recognition and authenticity verification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If optically variable effects such as tilting images are used in security features, then counterfeit protection is improved, but verification certainty deteriorates due to unclear transitions between images
Solution Approach 1:
The security feature is segmented into two distinct layers: a first laser-sensitive recording layer containing a positive representation and a second laser-sensitive recording layer containing a negative representation. This segmentation allows each layer to be optimized independently, with the positive layer providing clear verification from one direction and the negative layer providing clear verification from the opposite direction, eliminating the ambiguity of transitional states in traditional single-layer tilting images.
Solution Approach 2:
Each recording layer is assigned a specific local quality: the first layer contains a positive representation optimized for viewing from the first direction, while the second layer contains a negative representation optimized for viewing from the second direction. This local quality differentiation ensures that each layer contributes a distinct, verifiable characteristic that can be independently authenticated, thereby improving verification certainty while maintaining counterfeit protection.
2Measurement precision
If multiple laser-sensitive recording layers are used to introduce positives from different directions, then identifiability is improved, but device complexity increases
Solution Approach 1:
The invention merges the functionality of multiple recording layers into a unified security feature structure. The first and second laser-sensitive recording layers are combined in a single value document, with both layers working together to provide enhanced identifiability. The light-diffracting or light-refracting structures serve both layers simultaneously, allowing the system to achieve high measurement precision without proportionally increasing overall device complexity.
Solution Approach 2:
The light-diffracting or light-refracting structures serve multiple functions: they facilitate the introduction of the positive representation into the first recording layer from the first direction, and they also facilitate the introduction of the negative representation into the second recording layer from the second direction. This multi-functionality reduces the need for separate complex mechanisms for each layer, thereby limiting the increase in device complexity while improving identifiability.
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
This solution simplifies the identifiability and verification of the security feature, providing a tamper-proof tilt image with increased counterfeit protection, allowing for easier recognition and automated verification using standard card readers.
Implementation Method 1
positives of a representation are introduced by at least one laser beam
Implementation Method 2
laser-sensitive recording layer that is transparent in the visible spectral range
Implementation Method 3
light-diffracting or light-refracting structures arranged on a first side of the recording layer
Implementation Method 4
light-diffracting or light-refracting structures arranged on a first side of the recording layer
Implementation Method 5
laser-sensitive recording layer that is transparent in the visible spectral range
Data Source
AI summary
A security feature for a value document, into which positives of a representation are introduced by at least one laser beam, includes at least one laser-sensitive recording layer which is transparent in the visible spectral range, light-diffracting or light-refracting structures that are arranged on a first side of the recording layer, a positive and an image-processed positive. One of the positives or the image-processed positive is introduced into the at least one recording layer by a laser beam from a first direction through the light-diffracting or light-refracting structures and is visible when viewed from the first direction. The other of the positives or the image-processed positive is introduced into the at least one recording layer by a laser beam from a second direction and is visible when viewed from the second direction.