Security Device Merging Visible and UV Features
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Solution Overview
Problem
Existing security devices for documents require separate areas for visible and invisible features, making them bulky and difficult to integrate into small spaces, and often rely on specific narrow-band UV radiation, which limits their effectiveness.
Innovation Solution
A security device with regions containing materials that exhibit the same visible color under normal light but change to different colors under UV or IR illumination, allowing for a single feature that combines visible and invisible elements, using luminescent, photochromic, and thermochromic materials to achieve color matching and variability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate areas are used for visible and invisible security features, then security functionality is achieved, but device size increases and integration becomes difficult
Solution Approach 1:
The patent combines visible and invisible security features into a single integrated region by using ink compositions that contain both fluorescent pigments (for UV-visible features) and colorants (for visible features). This allows both types of security features to coexist in the same printed area, eliminating the need for separate regions and reducing overall device size.
Solution Approach 2:
The ink composition is designed to perform multiple functions simultaneously: it provides visible coloration through colorants, UV-induced fluorescence through fluorescent pigments, and color matching between visible and UV states. This multi-functionality allows a single ink layer to replace what would traditionally require separate ink layers or regions.
2Reliability
If narrow-band UV radiation is used for fluorescence activation, then specific security features are achieved, but effectiveness is limited and detection becomes easier
Solution Approach 1:
The patent broadens the UV wavelength range from narrow-band to wide-band (200-400 nm) to activate fluorescence in multiple fluorescent pigments simultaneously. This parameter change makes the security feature more difficult to detect and replicate because it requires a broader spectral understanding and wider-band UV sources, while still maintaining reliable fluorescence activation.
3Reliability
If multiple ink layers are used for visible and UV features, then security complexity increases, but manufacturing precision requirements increase
Solution Approach 1:
The patent merges multiple ink layers into a single ink composition containing both colorants and fluorescent pigments. This eliminates registration issues between layers and simplifies manufacturing while maintaining the ability to achieve color matching between visible and UV states through careful formulation of the combined ink composition.
4Ease of operation
If visible and invisible features are separated, then security inspection is simplified, but device complexity increases
Solution Approach 1:
The patent merges visible and invisible security features into a single printed region using an ink composition that contains both colorants and fluorescent pigments. This integration simplifies the overall device structure while maintaining inspection simplicity, as the combined feature can be viewed under different lighting conditions (visible light for color, UV light for fluorescence) without requiring separate physical regions.
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 enables compact integration of security features on documents, providing enhanced security by being difficult to replicate and detect, while allowing for a wide range of color effects and reduced size requirements, and operates effectively with various UV and IR wavelengths.
Implementation Method 1
Luminescent materials are known to those skilled in the art to include materials having fluorescent or phosphorescent properties
Implementation Method 2
Luminescent materials are known to those skilled in the art to include materials having fluorescent or phosphorescent properties
Implementation Method 3
It is also well known to use other materials that respond visibly to invisible radiation such as photochromic materials
Implementation Method 4
It is also well known to use other materials that respond visibly to invisible radiation such as photochromic materials and thermochromic materials
Data Source
AI summary
A security device comprises two or more regions (1, 2). Each region (1, 2) contains a material or combination of materials wherein the two or more regions exhibit substantially the same visible appearance under first viewing conditions and different visible appearances under second viewing conditions, the second viewing conditions. The second viewing conditions comprise a combination of a) visible light and b) substantially any UV wavelength.