Grating Image With Non-Smooth Field Edges for Anti-Counterfeit Security
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Solution Overview
Problem
Existing holographic diffraction structures in security documents lack advanced optical effects and are vulnerable to counterfeiting, necessitating improved security features that enhance authenticity and deter forgery.
Innovation Solution
A grid image comprising multiple adjacent grating fields with non-smooth-edged outlines and randomized grating line parameters, creating a diffuse visual appearance and enhanced security through electron beam lithography, combined with reflective or high-refractive-index materials and color-shifting thin-film structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional holographic diffraction structures are used, then security authentication is provided, but the structures lack advanced optical effects and are vulnerable to counterfeiting
Solution Approach 1:
The grating image is divided into multiple adjacent grating fields (first, second, third, and fourth grating fields) with different orientations and visual appearances. Each grating field contains dashed grating lines with specific orientations that create different visual effects when viewed from different angles, providing both security authentication and advanced optical effects through segmented design
Solution Approach 2:
Different regions of the grating image are assigned different local properties: the first and second grating fields have grating lines oriented in a first direction, while the third and fourth grating fields have grating lines oriented in a second direction perpendicular to the first. This local differentiation creates diverse optical effects while maintaining overall security functionality
2Ease of manufacture
If smooth-edged grating fields are used, then manufacturing is simpler, but the security against counterfeiting is reduced
Solution Approach 1:
The grating fields are designed with non-smooth-edged outlines featuring asymmetric patterns including protrusions and recesses at the boundaries between adjacent grating fields. These asymmetric edge features are difficult to replicate and provide enhanced security against counterfeiting while maintaining manufacturability through precise fabrication processes
3Adaptability or versatility
If multiple grating fields with different orientations are used, then visual appearance and optical effects are enhanced, but the complexity of the grating image increases
Solution Approach 1:
The complex visual effects are extracted and achieved through the interaction of light with the specifically oriented dashed grating lines in different grating fields. The dashed line patterns and their orientations are designed to create apparent motion and visual changes when viewed from different angles, providing enhanced visual appearance without requiring physically complex structures
Solution Approach 2:
The grating image utilizes the angular dimension by arranging grating fields with different orientations (first direction and second perpendicular direction). This creates the illusion of motion and changes in visual appearance as the viewing angle changes, adding a dimensional aspect to the security feature without increasing physical complexity
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 a secure, visually appealing grid image with a diffuse pumping effect, resistant to counterfeiting and suitable for automated production, offering improved security and efficiency in manufacturing.
Implementation Method 1
each grating pattern has a preferred direction that defines a viewing angle from which the respective grating pattern is visually recognizable
Implementation Method 2
A contour area between two grid fields that has tapered projections and tapered indentations is referred to as sawn... upon observation, exhibit scattering effects rather than diffractive effects and have a matte appearance
Data Source
Figure 1~2
Figure 3a~3b
Figure 4~5
AI summary
The invention relates to a grating image (40) having a multiplicity of mutually adjoining grating fields (G0, G1, G2) having a diffuse, viewing-angle-dependent visual appearance, wherein each grating field (G0, G1, G2) is filled within its contour with a grating pattern (M0, M1, M2) composed of a multiplicity of straight ruled grating lines, wherein each grating pattern (M0, M1, M2) has a preferred direction that defines a viewing angle from which the respective grating pattern (M0, M1, M2) is visually discernible. According to the invention, in this case at least two mutually adjoining grating fields (G1, G2) have in each case a non-smooth-edged contour (34) along their common contour region.