Imprinted Security Lens Pattern for Tamper-Resistant Documents
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing security devices have coarse security patterns and a stepped surface design that can be tampered with, and require immediate application of a protective layer over the photograph, limiting personalization and security feature application.
Innovation Solution
A method involving a flexible and transparent imprint member to create small-scale lens patterns in the protective layer, followed by laser engraving of blackened images in the base layer, allowing for enhanced security features and remote personalization of security documents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a transparent curable resin is applied by ink jet printing to form security patterns, then the protective layer resists removal of the photograph, but the printed security pattern is relatively coarse with dimensions in the range of 1 or more mm
Solution Approach 1:
The patent replaces the mechanical ink jet printing system with an optical imprinting system using a relief imprint member. The pattern is transferred through optical contact and UV curing rather than mechanical deposition, enabling much finer pattern dimensions (sub-100 μm vs. 1+ mm) while maintaining protective layer integrity and anti-removal properties
Solution Approach 2:
The patent changes the dimensional parameter of the security pattern from millimeter-scale (ink jet printing) to sub-100 micrometer scale (imprinting). This parameter change is achieved by using a relief imprint member with fine features that can be optically contacted and cured, transforming the pattern resolution capability while maintaining the protective function
2Illumination intensity
If a photograph is positioned on top of the top side of the security device, then the photograph can be clearly displayed, but it forms a stepped surface which may present an access point for tampering or attempted removal
Solution Approach 1:
The patent merges the photograph layer with the protective layer by applying the curable resin directly over the photograph and curing it in place. This creates a unified, flush surface where the photograph is embedded within the hardened protective matrix, eliminating the stepped surface while maintaining photograph visibility and adding anti-tampering security
Solution Approach 2:
The patent applies the protective resin layer before final positioning and curing, creating a preliminary protective structure that is then cured to lock the photograph in place. This preliminary action of applying resin first, then curing, prevents subsequent tampering while maintaining the photograph's display function
3Reliability
If a resin curable layer is applied over the photograph as a protective layer, then the photograph is protected, but it requires application of the protective layer immediately following application of the photograph to prevent damaging the photograph or unauthorized alteration
Solution Approach 1:
The patent segments the security device production into distinct modules: base layer preparation, photograph application, resin coating, and UV curing. This segmentation allows the photograph to be applied at one location and time, while the protective layer is applied and cured in a controlled subsequent step, enabling remote personalization while maintaining photograph protection
Solution Approach 2:
The patent introduces a controllable resin coating system as an intermediary between photograph application and final protection. The resin is applied in a controlled manner and immediately cured by UV light, creating a protective barrier without requiring immediate manual intervention. This intermediary process enables flexibility in personalization while ensuring photograph protection
4Reliability
If the protective layer is hardened by irradiating it with optical radiation, then the protective layer is cured, but the coarse pattern limits the definition of small-scale security features
Solution Approach 1:
The patent replaces the ink jet mechanical deposition system with an optical imprinting system. The relief imprint member transfers the pattern through optical contact, and UV curing hardens the resin. This substitution enables sub-100 μm pattern definition because the imprint member can be fabricated with fine features that are transferred directly through optical contact, rather than being limited by ink jet droplet size
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 method achieves well-defined small-scale security features independent of the color image, preventing 'flip' effects and enabling secure, remote personalization of security documents with improved security and aesthetics.
Implementation Method 1
hardening of the protective layer by irradiating it with optical radiation
Implementation Method 2
providing a blackened pattern into the base layer by focusing a laser beam via the optical structure and laser engraving image elements into the base layer
Implementation Method 3
focusing a laser beam via the optical structure
Data Source
AI summary
Disclosed is a method of forming a security document including the steps of: providing a base layer having a top side; providing a color image onto an image area of the top side by printing colored ink, on the top. A lens structure is applied over the colored ink, the lens structure having a predetermined focal plane situated at a distance from the top side, and laser engraving a black image in through the lens structure and through the colored ink to form blackened image elements substantially at or near the focal plane.