Laser Engraving Layered Structure for ID Documents
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Solution Overview
Problem
Existing methods for laser engraving of security documents, such as identification cards, face challenges with agglomerates forming during high concentrations of laser-sensitive pigments, leading to poor sharpness and resolution due to increased greying of the base material.
Innovation Solution
A layered structure comprising a thermoplastic plastic layer with a black pigment as a laser-sensitive additive, where the layer thickness is between 5 to 30 μm and the additive concentration is between 40 to 180 ppm, ensuring improved transparency and absorption for enhanced laser engraving quality without excessive greying.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high concentrations of laser-sensitive pigments are used for laser engraving, then the laser engraving capability is improved, but agglomerates form causing burners and increased greying of the base material, which impairs sharpness and resolution
Solution Approach 1:
The patent applies parameter changes by precisely controlling the concentration of laser-sensitive pigments (carbon black) within a specific range of 1 to 200 wt. ppm, and by controlling the layer thickness between 5 to 30 μm. This optimization prevents agglomerate formation while ensuring sufficient laser absorption, thereby achieving both reliable engraving capability and high sharpness and resolution without excessive greying of the base material
Solution Approach 2:
The patent uses composite materials by combining thermoplastic plastic with controlled amounts of laser-sensitive pigments (carbon black) in a multi-layer structure. This composite approach allows the pigment to be distributed uniformly at optimal concentrations, preventing agglomeration while maintaining effective laser absorption properties for high-quality engraving
2Object-affected harmful factors
If low concentrations of carbon black are used for laser engraving, then greying of the base material is reduced, but the sharpness and resolution of the lettering or image are not optimal
Solution Approach 1:
The patent resolves this contradiction by identifying the optimal concentration range for carbon black (1 to 200 wt. ppm) and layer thickness (5 to 30 μm). Within this range, the material achieves sufficient laser absorption for high sharpness and resolution while minimizing greying of the base material, finding the optimal balance point between these two parameters
3Manufacturing precision
If the layer containing laser-sensitive additive is made thin to improve sharpness and resolution, then the contrast is impaired due to increased greying
Solution Approach 1:
The patent resolves this contradiction by optimizing both layer thickness (5 to 30 μm) and pigment concentration (1 to 200 wt. ppm) simultaneously. This dual parameter optimization ensures that even at thin layer thicknesses, sufficient laser absorption occurs to maintain good contrast, while the controlled concentration prevents excessive greying that would impair visibility
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 approach achieves improved sharpness and resolution in laser-engraved images on security documents without the adverse effect of increased greying, ensuring high-quality inscription with optimal color effect.
Implementation Method 1
at least one layer having a layer thickness of from 5 to 30 μm and containing at least one thermoplastic plastic and at least one black pigment as laser-sensitive additive
Data Source
AI summary
The present invention relates to a layer structure having improved properties for laser engraving, to particular embodiments of said layer structures in the form of co-extrusion films, and to security documents, preferably identification documents having said layer structures.