Anti-counterfeit Thread with Asymmetric Micro-character Visibility
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Solution Overview
Problem
Conventional counterfeit preventive papers and printed materials with embedded threads display micro-characters that are visible in opposite directions when viewed from the obverse and reverse sides, which can compromise their effectiveness in preventing counterfeiting and may not meet the needs of applications requiring consistent image orientation or hidden authenticity verification.
Innovation Solution
A thread with a light-permeable substrate featuring a metal thin film layer and a colored resin layer patterned on both sides, where the difference in light permeability between regions with and without the metal film creates contrast, allowing the pattern to be visible from one side while appearing nonexistent from the other, using the demetallizing process to form micro-characters that can be viewed consistently or hidden as needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional threads with micro-characters are used in counterfeit preventive paper, then the thread provides security features, but the micro-characters appear in opposite directions when viewed from obverse and reverse sides, compromising authentication consistency
Solution Approach 1:
The patent applies asymmetry by making the thread structure non-symmetric with respect to the paper surface. The thread is positioned asymmetrically within the paper thickness, closer to one side, which causes light to interact with the micro-characters differently depending on the viewing side. This asymmetric positioning ensures that micro-characters appear in the same orientation when viewed from both obverse and reverse sides, resolving the contradiction between authentication consistency and visibility direction.
Solution Approach 2:
The patent transitions from a two-dimensional surface problem to a three-dimensional spatial solution. Instead of trying to control character orientation on the surface, the invention uses the third dimension (depth within the paper) by positioning the thread at a specific depth. This dimensional change allows light to pass through the paper and thread in a way that preserves consistent character orientation from both sides, solving the visibility direction issue while maintaining authentication reliability.
2Adaptability or versatility
If the thread is made with metal thin film layer for decorative and security effects, then the aesthetic value and security are enhanced, but the manufacturing complexity increases due to demetallizing process requirements
Solution Approach 1:
The patent applies preliminary action by pre-forming the metal thin film layer with the desired micro-character patterns on the thread before inserting it into the paper. The demetallizing process is performed in advance on the thread itself, creating the security features and aesthetic patterns beforehand. This preliminary preparation simplifies the overall manufacturing process by separating complex operations from the paper making process, reducing the complexity that would otherwise be embedded in the device or system.
Solution Approach 2:
The patent segments the manufacturing process into distinct independent stages: thread production (including metal deposition and demetallizing) and paper production (including thread insertion). By dividing the overall process into separate modules, each with specific functions, the complexity is distributed and managed more easily. The metal thin film layer processing is segmented from the paper making process, allowing specialized equipment and methods to be used for each stage without complicating the entire system.
3Strength
If windowed threaded paper is made with heat-sensitive adhesive to prevent thread peeling, then the thread adhesion is improved, but the manufacturing process complexity increases due to additional drying zone requirements
Solution Approach 1:
The patent applies parameter changes by utilizing the existing drying zone temperature parameters of the paper machine to activate the heat-sensitive adhesive. Instead of adding new equipment or processes, the invention changes the state of the adhesive from inactive to active by exploiting the temperature parameter already present in the drying zone. This approach improves thread adhesion strength while avoiding additional device complexity, as the temperature parameter is already part of the standard paper making process.
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 thread enhances counterfeit prevention by ensuring micro-character visibility in the same direction from both sides when viewed with reflected light and allows for shadow recognition with transmitted light, improving the commercial value and security of documents like passports and banknotes, while also being applicable in decorative and entertainment contexts.
Implementation Method 1
due to difference in light permeability between a region having the metal thin film layer and a region not having the metal thin film layer, a contrast is caused between the former region and the latter region when held to light
Implementation Method 2
by making windowed threaded paper using the thread having a heat-sensitive adhesive on the surface thereof, and fusing or softening the heat-sensitive adhesive applied on the thread when drying the paper in a drying zone of the paper machine
Data Source
Figure 1~3
Figure 4~6
Figure 7~10
AI summary
The invention provides a thread and counterfeit preventive paper satisfying the conditions that, when the micro-character of the thread is viewed from one side and opposite side of the paper or printed material, the image of micro-character can be recognized in the same direction from any side, not in opposite direction to each other, and that, when viewed from the opposite side, the image of the corresponding micro-character is not visible. The counterfeit preventive paper 10 and counterfeit preventive printed material have a structure in which a thread 1 having metal deposition layers 3, 4 formed in a pattern of micro-character and colored printed layers 7, 8 formed thereon provided on both sides of a strip-like and light permeable substrate 2 is inserted between paper layers 15a, 15b.