Latent Image Security Feature Using Logical Operations
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Solution Overview
Problem
Existing latent image security features for documents, such as banknotes and passports, face challenges in maintaining legibility and matching patterns while being difficult to counterfeit, often resulting in distorted or less legible designs due to the use of multiple small areas or strong distortions.
Innovation Solution
A latent image security feature is created by superimposing two images with patterns of lines extending in different directions, using logical operations like negation of implication, simultaneous negation, or reverse implication to form a convex structure that is easy to produce and difficult to counterfeit, utilizing the Intaglio printing technique with opaque or transparent ink and embossing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple small areas are used to combine latent images, then the security feature becomes more complex and harder to counterfeit, but the legibility and pattern coherence deteriorate
Solution Approach 1:
The patent divides the latent image into multiple segments arranged in a grid pattern, where each segment contains a portion of the latent image. This segmentation allows the security feature to maintain high counterfeiting resistance through complex multi-angle viewing requirements while preserving legibility by ensuring all segments collectively form the complete, coherent image when viewed from the correct angle
Solution Approach 2:
The patent introduces a temporal dimension to the security feature by requiring sequential viewing from multiple angles (0°, 45°, 90°) to progressively reveal different segments of the latent image. This multi-angular temporal sequence creates a dynamic viewing experience that enhances security while maintaining pattern coherence through the progressive revelation of the complete image
2Reliability
If strong distortions are applied to create latent images, then the security feature becomes more secure, but the pattern coherence and visual quality deteriorate
Solution Approach 1:
The patent applies asymmetric distortion specifically to the vertical dimension of the latent image pattern while preserving horizontal proportions. This selective asymmetric distortion creates a security feature that is difficult to counterfeit due to its complex transformation requirements, while the controlled nature of the distortion maintains pattern coherence and visual quality when viewed from the intended angle
3Reliability
If Intaglio printing technique is used to create convex structure, then the security feature becomes more secure and difficult to counterfeit, but the manufacturing complexity and cost increase
Solution Approach 1:
The patent incorporates the latent image pattern directly into the intaglio printing form during the form creation stage, rather than requiring separate application steps. This preliminary integration of the latent image design into the printing form itself simplifies the manufacturing process while maintaining the security benefits of the intaglio convex structure
Solution Approach 2:
The patent merges the latent image creation process with the standard intaglio printing process by integrating the latent image pattern into the printing form design. This consolidation combines multiple functions (security feature creation, pattern printing, convex structure formation) into a single manufacturing step, reducing overall manufacturing complexity while maintaining high counterfeiting resistance
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, legible, and cost-effective security feature that is resistant to counterfeiting, maintaining a uniform appearance when viewed at different angles and ensuring the pattern remains cohesive without visible division or distortion.
Implementation Method 1
When viewing an element made as described above at an acute angle, the convexity of the lines perpendicular to the observer results in an optical masking of gaps between given images. Thus, a uniform surface becomes visible.
Implementation Method 2
The latent image is filled with parallel lines of a given thickness and with strictly defined spacing. It is placed on the background of another image, which is also filled with lines, which in this case are, however, perpendicular to those in the latent image. The latent image can be a freely 'suspended' graphic element or a part of a larger image. Elements combined in such a way are printed using the Intaglio technique. This means that the pattern is convex in relation to the substrate.
Data Source
Figure 1a~1d
Figure 2
Figure 3
AI summary
A latent image security feature for a security document, comprises a substrate with a convex structure emerging by superimposing at least two images, wherein one of the images is defined by at least one pattern of lines extending in the first direction, the other of the images is defined by a pattern of lines extending in the second and third directions forming together a latent image, with the first, second and third directions being different. The security feature is characterised in that the convex structure is defined by the resultant latent image formed by performing one of three logical operations on the first image and the second image, wherein the operations are as follows: negation of implication, simultaneous negation, reverse implication.