Security Thread with Stacked Fluorescent and Phosphorescent Layers
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Solution Overview
Problem
Current security structures incorporating luminescent substances lack innovative effects to enhance observer appeal and counterfeiting resistance, particularly under naked eye or low magnification, and require improved optical effects observable with UV or IR illumination.
Innovation Solution
A security structure comprising simultaneously excitable fluorescent and phosphorescent compositions that emit lights combinable or juxtaposable to produce distinct optical effects, with the ability to change appearance or contrast when illuminated and extinguished, using UV or IR light at 365 nm, and optionally integrated with opaque perforated layers and UV radiation barriers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple luminescent substances are used to create new optical effects, then observer appeal and security against counterfeiting are improved, but the structure complexity and difficulty of detection increase
Solution Approach 1:
The patent combines fluorescent and phosphorescent compositions in a single security structure, allowing both luminescent effects to coexist and interact. This merging of different luminescent mechanisms creates complex optical effects that are difficult to counterfeit while maintaining a unified structure rather than separate components.
Solution Approach 2:
The patent introduces temporal dimension by utilizing the different persistence characteristics of fluorescent and phosphorescent materials. The phosphorescent component continues to emit light after the excitation source is removed, creating a time-based security feature that adds a new dimension to detection and verification.
2Reliability
If fluorescent and phosphorescent compositions are used simultaneously, then unique optical effects are produced, but the difficulty of detecting and measuring the effects increases
Solution Approach 1:
The patent utilizes the periodic activation and deactivation of the excitation source to differentiate between fluorescent and phosphorescent effects. By turning the UV light on and off, observers can distinguish which components continue to emit light after excitation ceases, providing a simple temporal method to detect and measure the different luminescent properties.
Solution Approach 2:
The patent employs fluorescent and phosphorescent compositions that emit different colors or color combinations, making the security features visually distinguishable. The fluorescent composition typically emits a specific color under UV illumination, while the phosphorescent composition may emit a different color that persists after the UV source is removed, creating detectable color variations.
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 enhances observer appeal and counterfeiting resistance by creating unique optical effects that change with illumination, providing enhanced security features observable under specific lighting conditions, thereby improving document authentication.
Implementation Method 1
at least one first fluorescent composition, at least one second phosphorescent composition, the first and second compositions being excitable simultaneously by a predefined illuminant from the same first face of the structure
Implementation Method 2
at least one second phosphorescent composition, the first and second compositions being excitable simultaneously by a predefined illuminant from the same first face of the structure
Data Source
Figure 1~10
Figure 3A~4B
Figure 3C~13
AI summary
The present invention relates to a security structure (10), comprising at least one first fluorescent composition (13) and at least one second phosphorescent composition (12), the first and second compositions being simultaneously excitable by a predefined illuminant from a single first surface (14) of the structure, the security structure (10) being provided in the form of a security thread, a security film, or a patch, wherein the first fluorescent composition is at least partially stacked on the second phosphorescent composition and/or the first and second compositions are used for the reference marking on the security structure.