Multilayer Security Document Color Laser Marking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing color laser marking technologies for security documents face issues with non-selective bleaching of colorants, leading to undesired color changes and a limited color gamut, making it difficult to achieve pure magenta and cyan colors, which affects the image quality and authenticity of security documents.
Innovation Solution
A multilayer assembly with separate layers, each containing a specific bleachable color component, is used, where the order of layers is configured based on absorption coefficients and effective laser reactivity to selectively filter and transmit laser wavelengths, preventing unwanted bleaching and expanding the color gamut.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single layer with a mixture of colorants is used for laser marking, then the process is simple, but the color selectivity is poor leading to undesired color changes
Solution Approach 1:
The patent divides the single layer structure into multiple separate layers, each containing specific colorants with complementary absorption properties. This segmentation allows each layer to selectively absorb specific laser wavelengths while transmitting others, thereby improving color selectivity and preventing undesired color changes during laser marking.
Solution Approach 2:
The patent uses composite layer structures where each layer is composed of specific colorant combinations designed to have complementary absorption spectra. These composite materials work together to achieve precise wavelength-selective bleaching, enabling accurate color reproduction while maintaining process simplicity.
2Adaptability or versatility
If conventional colorants with wide absorption bands are used, then the material selection is easier, but the color gamut is limited and pure primary colors cannot be achieved
Solution Approach 1:
The patent assigns different absorption characteristics to different layers based on their specific functions. Each layer is optimized with colorants that have complementary absorption bands, creating local quality variations that collectively expand the overall color gamut while enabling pure primary color production through selective bleaching.
Solution Approach 2:
The patent changes the absorption parameters of colorants by selecting specific materials with complementary absorption characteristics for different layers. This parameter optimization allows each layer to respond selectively to specific laser wavelengths, expanding the achievable color gamut and enabling pure primary colors while maintaining ease of material selection.
3Manufacturing precision
If multiple layers with different color components are used, then the color gamut is expanded, but the structure becomes more complex
Solution Approach 1:
The patent segments the colorant system into multiple functional layers, each with a specific absorption profile. This segmentation expands the color gamut by enabling independent control of different color channels, while the modular layer structure actually simplifies the overall design and manufacturing process compared to attempting to achieve the same color performance in a single complex mixture.
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 enhances the color gamut and image quality, allowing for the production of pure primary colors like magenta and cyan, thereby improving the security and authenticity of marked documents.
Implementation Method 1
the order of layers is configured based on absorption coefficients and effective laser reactivity to selectively filter and transmit laser wavelengths
Implementation Method 2
each comprising a specific bleachable color-forming component... When exposed to such wavelength, the color component undergoes full bleaching or passes from one chromatic color to a different chromatic color
Implementation Method 3
Under laser irradiation, the embedded pigments undergo color changes, resulting in the visual appearance of marks of targeted colors
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The present invention relates generally to a data carrier and a method for making the data carrier. More particularly, this invention relates to color laser marking of article, especially security documents. The present invention proposes a security document comprising a multilayers assembly instead of a single color component mixture in a layer. The multilayer assembly comprises at least two laser sensitive layer. Each layer comprises at least one coloring agent component. The order arrangement of the multilayers of bleachable coloring agent component is made so that each layer behaves as a wavelength filter configured to selectively transmit longer wavelengths and block or attenuate shorter wavelengths while protecting the underneath coloring agent component from bleaching interference.