Laser-Marking Multilayer Sheet for Electronic Passports
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Solution Overview
Problem
Existing laser-marking multilayer sheets for electronic passports face challenges in displaying clear personal information, such as names, symbols, and photographs, with high contrast and thermal resistance, while also preventing falsification and forgery.
Innovation Solution
A five-layer laser-marking multilayer sheet structure comprising a transparent laser-marking multilayer sheet A and a colored laser-marking multilayer sheet B, with a film C, where each layer is formed using coextrusion methods and includes specific resin compositions and additives for enhanced thermal adhesiveness, flexibility, and laser-marking properties, allowing for easy attachment to electronic passport covers and preventing forgery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a laser-marking multilayer sheet is used for electronic passports, then clear personal information with high contrast can be displayed, but the sheet may be damaged by laser beam irradiation or show insufficient thermal resistance
Solution Approach 1:
The sheet is divided into multiple functional layers: a transparent resin layer (50-150 μm) that transmits laser beams for marking, and a heat-resistant resin layer (50-250 μm) that absorbs laser energy and provides thermal resistance. This segmentation allows each layer to specialize in its function, resolving the contradiction between clarity and thermal resistance.
Solution Approach 2:
The invention uses a composite structure combining transparent resin (for laser transmission and clear marking) with heat-resistant resin containing energy absorbers like carbon black or metal oxides (for thermal resistance). The composite material approach enables simultaneous achievement of optical transparency for clear display and thermal stability for reliability.
2Weight of moving object
If the multilayer sheet is made thin and light to meet passport standards, then portability is improved, but the ability to display clear images and text with high contrast deteriorates
Solution Approach 1:
Instead of increasing thickness for clarity, the invention improves marking quality through the optical and thermal properties of the resin composition in the existing thin layer. The transparent resin layer with specific thickness (50-150 μm) and composition enables clear laser marking without increasing overall passport weight, resolving the contradiction by operating in the dimension of material properties rather than geometric thickness.
3Productivity
If the multilayer sheet structure is simplified to improve manufacturing, then productivity increases, but the ability to prevent falsification and forgery deteriorates
Solution Approach 1:
The heat-resistant resin layer is pre-formed with energy absorbers (carbon black, metal oxides, or metal sulfides) incorporated during manufacturing. This preliminary preparation of thermal properties enables subsequent laser marking and anti-falsification features to be added without complex post-processing, maintaining high productivity while achieving security requirements.
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 clear and high-contrast laser-marked letters, symbols, and images with excellent thermal adhesiveness, sheet conveyance, and thermal resistance, effectively inhibiting falsification and enhancing the security of electronic passports.
Implementation Method 1
an internal layer of a thermoplastic resin composition containing 0.01 to 5 parts by weight of an energy absorber absorbing a laser beam
Data Source
Figure 1~2
Figure 3
AI summary
There is provided a laser-marking multilayer sheet for an electronic passport formed by laminating five sheets of a multilayer sheet A / a multilayer sheet B / a film C / a multilayer sheet B / a multilayer sheet A. The multilayer sheet B is a colored laser-marking multilayer sheet. The film C is a laser-marking multilayer sheet made of a film for the electronic passport. The laser-marking multilayer sheet can have clear letters, symbols, and images, which are excellent in a laser-marking property and high in contrasts between the original surface color and the printed portions. The laser-marking multilayer sheet is excellent especially for inhibiting the falsification and forgery thereof.