Filtering Layer for Dual UV Photoluminescent Images
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Solution Overview
Problem
Existing security methods for official documents fail to effectively display images sensitive to short-wave and long-wave ultraviolet light on the same document without interference, leading to poor rendering of images visible under short-wave ultraviolet light when superposed with those visible under long-wave ultraviolet light.
Innovation Solution
A document with a filtering layer that allows wavelengths from a short-wave ultraviolet light source to be filtered, enabling clear visibility of an image sensitive to long-wave ultraviolet light without obstructing the view of an image sensitive to short-wave ultraviolet light, allowing both types of images to be displayed independently on the same document.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an image visible under long-wave ultraviolet light and an image visible under short-wave ultraviolet light are superposed on the same document, then the security level is increased, but the image visible under short-wave ultraviolet light is poorly rendered and cannot be effectively inspected
Solution Approach 1:
A filtering layer is introduced as an intermediary element between the two photoluminescent images. This filtering layer selectively transmits short-wave ultraviolet light while blocking long-wave ultraviolet light, enabling clear inspection of the short-wave image without interference from the long-wave image's photoluminescent emission. The filtering layer thus mediates the optical interaction between the two images, allowing both to coexist on the same document with high rendering quality.
2Loss of information
If multiple sources of non-visible light are used simultaneously to view different photoluminescent images, then more information is available, but the images interfere with each other and cannot be clearly distinguished
Solution Approach 1:
The optical inspection process is segmented into distinct wavelength channels using a filtering layer. The filtering layer segments the ultraviolet spectrum by transmitting short-wave ultraviolet light while blocking long-wave ultraviolet light. This segmentation allows each photoluminescent image to be inspected independently in its designated wavelength channel, eliminating cross-interference and enabling clear distinction between the two images while maintaining full information availability.
3Adaptability or versatility
If an image sensitive to long-wave ultraviolet light is applied on the same document as an image sensitive to short-wave ultraviolet light, then authentication capability is enhanced, but the long-wave image activates under short-wave illumination causing interference
Solution Approach 1:
The filtering layer converts the harmful effect of long-wave photoluminescent activation under short-wave illumination into a beneficial selective transmission property. By designing the filtering layer to block long-wave ultraviolet light while transmitting short-wave ultraviolet light, the system eliminates the harmful interference caused by the long-wave image activating under short-wave illumination. This transforms the potential problem of cross-activation into a solution where each image type is optimally viewed under its designated wavelength without interference.
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
This solution enhances the security and authentication of official documents by allowing high-quality visualization of images under respective ultraviolet light sources, increasing authentication levels and preventing interference between images.
Implementation Method 1
a layer, named filtering layer, superposed on said second image and comprising at least one material, named filtering material, suitable for allowing the wavelengths emitted by said first source of non-visible light to be filtered
Implementation Method 2
at least one pigment which is photoluminescent under illumination by said first source of non-visible light
Data Source
AI summary
A document (15) includes at least:one first image (5) including at least one photoluminescent pigment which is invisible under illumination in visible light and is visible under illumination by at least one first source (20) of non-visible light emitting in the short ultraviolet domain,one second image including at least one photoluminescent pigment which is invisible under illumination in visible light and is visible under illumination by at least one second source of non-visible light emitting in the long ultraviolet domain,one layer, named a filtering layer, arranged facing the second image and including at least one material, named a filtering material, suitable for allowing the wavelengths emitted by the first source of non-visible light to be filtered without preventing the first image from being seen under illumination by the first light source.