Halftone Printing Grid With Circular Arcs For Authenticity Verification
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Solution Overview
Problem
Current technologies for verifying the authenticity of printed articles, such as banknotes and identification documents, lack effective methods to ensure forgery-proofness using halftone printing technology, making it difficult to easily verify the authenticity of such documents.
Innovation Solution
A printed article with a circular arc-based printing grid and a test device featuring a transparent test surface with a matching test print grid, allowing for the creation of a unique moiré image when overlaid, enabling easy authenticity verification by producing a distinct moiré image that differs from standard moiré patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional halftone printing technology is used, then printing capability is achieved, but authenticity verification capability is insufficient
Solution Approach 1:
The patent applies curvature by replacing conventional straight grid lines with circular arcs in the halftone screen. Each halftone dot is positioned at the intersection of circular arcs instead of straight lines, creating a curved grid pattern that generates distinctive moiré effects during verification. This curved geometry provides a simple yet effective means to enhance authenticity verification without adding complex printing mechanisms.
2Reliability
If standard moiré pattern verification is used, then verification capability exists, but the patterns are easily replicated by counterfeiters
Solution Approach 1:
The patent introduces asymmetry by using circular arcs with different radii for the vertical and horizontal grid lines. The vertical arcs have one radius while the horizontal arcs have a different radius, creating an asymmetric curved grid pattern. This asymmetric design produces unique moiré patterns that are difficult to replicate, thereby enhancing forgery resistance while maintaining verification simplicity through visual inspection.
3Reliability
If halftone dots are arranged on closed circular arcs, then a specific pattern is achieved, but the pattern may be too complex for easy verification
Solution Approach 1:
The patent applies local quality by using circular arcs with sufficiently large radii that create only slight curvatures in the grid lines. This local approximation of circular arcs to straight lines allows the human eye to easily detect the moiré patterns during verification, while still providing enough curvature to generate unique verification patterns. The subtle curvature maintains detectability while enhancing authenticity verification.
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 allows for a straightforward verification of the printed article's authenticity through the formation of a characteristic moiré image, enhancing security features and preventing forgery by utilizing a circular arc-based printing grid and matching test print grid, which can be applied to various documents and materials.
Implementation Method 1
The print grid of the test specimen and the test print grid of the test instrument are shifted relative to one another, for example rotated, until a moiré pattern becomes visible for the print grid and the test print grid
Data Source
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AI summary
The invention relates to a printed article (1), comprising a visible surface (2) and a printed surface (3), arranged in the region of the visible surface (2), wherein the printed surface (3) is printed with a halftone (4), wherein halftone dots (5) are arranged at a respective consistent distance along halftone lines (6), each of which is an arc. The invention also relates to a method for checking the authenticity of a printed article and an article system.