Banknote Validator Using Luminescence Color Sensors
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Solution Overview
Problem
Existing banknote validators face challenges in miniaturization and cost due to the need for separate intense light sources and complex mechanisms for distinguishing denominations, especially for handheld devices used by visually impaired individuals, as they struggle to accurately discriminate between genuine and counterfeit banknotes using reflectance, transmittance, and luminescence intensities.
Innovation Solution
A banknote validator employing color sensors with filters to measure luminescence color values under UV illumination, using multiple UV light sources and a single RGB photodiode to determine mean wavelength and amplitude, allowing for precise denomination identification and authentication, and incorporating additional light sources for decay time measurement and counterfeit detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate intense pulsed light sources and adapted lenses are used to obtain measurement data with good signal/noise ratio, then measurement precision is improved, but device complexity and cost increase, making miniaturization more difficult
Solution Approach 1:
The patent combines multiple light sources (UV, white, IR) and multiple sensors (photodiodes, photomultipliers) into a single integrated scanning head assembly. This merging approach maintains measurement precision by capturing multiple spectral characteristics simultaneously while reducing device complexity through unified structural design, directly resolving the contradiction between measurement quality and device simplicity.
Solution Approach 2:
The scanning head is designed as a multi-functional unit that can perform reflectance measurement, transmittance measurement, and luminescence detection using the same physical structure. The universal design eliminates the need for separate dedicated components for each measurement type, thereby maintaining measurement precision while reducing overall device complexity and enabling miniaturization.
2Measurement precision
If separate intense pulsed light sources and adapted lenses are used to obtain measurement data with good signal/noise ratio, then measurement precision is improved, but manufacturing cost increases
Solution Approach 1:
By integrating multiple light sources and sensors into a single scanning head module, the patent reduces the total number of separate components that need to be manufactured and assembled. This merging strategy maintains measurement precision through comprehensive optical coverage while lowering manufacturing costs through reduced component count and simplified assembly processes.
Solution Approach 2:
The patent employs photomultiplier tubes and specialized photodiodes with optimized spectral response characteristics to enhance signal detection capability. By carefully selecting and optimizing sensor parameters (spectral sensitivity, gain, noise characteristics), the system achieves good signal/noise ratio without requiring excessively expensive high-power light sources, thus balancing measurement precision with manufacturing cost.
3Device complexity
If reflectance or transmittance intensities or luminescence intensity are used for detection, then device complexity is reduced, but discrimination capability between denominations and counterfeit banknotes is insufficient
Solution Approach 1:
The patent transitions from one-dimensional intensity measurement to multi-dimensional spectral analysis by simultaneously measuring reflectance, transmittance, and luminescence characteristics across different wavelength ranges (UV, visible, IR). This dimensional expansion provides rich spectral signatures that enable precise discrimination between banknote denominations and counterfeit notes while maintaining relatively simple device architecture through integrated sensing.
Solution Approach 2:
The scanning head employs a composite optical detection system combining multiple types of sensors (photodiodes, photomultipliers) with different spectral sensitivities and multiple light sources emitting at different wavelengths. This composite approach creates a comprehensive detection capability that enhances discrimination capability while keeping device complexity manageable through unified integration.
4Measurement precision
If imaging of specific marking or detection of marking with magnetic ink or conductivity properties is used to discriminate denominations, then discrimination capability is improved, but device complexity increases due to need for transport mechanisms and control means
Solution Approach 1:
The patent replaces mechanical transport mechanisms with an optical scanning approach. Instead of physically moving the banknote through a passageway with magnetic or conductivity sensors, the system uses UV, white, and IR light sources to illuminate and detect luminescent markings directly on the banknote surface. This substitution eliminates complex mechanical control means while maintaining or improving discrimination capability through multi-spectral optical detection.
Solution Approach 2:
The patent introduces luminescent markings as an intermediary feature that carries denomination information. By detecting the luminescence characteristics of these markings under UV illumination, the system can identify denominations without needing direct contact with magnetic or conductivity marking systems. The luminescent marking serves as an optical intermediary that simplifies the detection mechanism while providing robust discrimination capability.
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 reliable and precise denomination identification and authentication, reduces the need for complex transport mechanisms, and miniaturizes the device, making it suitable for handheld use while improving discrimination against counterfeit banknotes.
Implementation Method 1
a marking operable to glow with a specific color luminescence according to the denomination under appropriate UV light illumination
Implementation Method 2
Some banknotes validators can further detect the presence of fluorescent and/or phosphorescent material (i.e. luminescent material) on or within the banknotes
Implementation Method 3
under illumination by appropriate light (for example, UV, white or IR light)
Implementation Method 4
using color sensors, i.e. not mere fluorescence sensors for measuring only fluorescent light intensities, but photodiodes equipped with filters (for receiving a luminescence light only within a wavelength window)
Data Source
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AI summary
The present invention relates to the technical field of devices for reading/authenticating banknotes. The invention also concerns handheld devices, particularly those which may be used by visually impaired persons, to identify different banknote denominations. The present invention is aimed at providing a banknote validator that avoids the drawbacks of the prior art. The validator according to the invention may as well be used for validating a security document including a marking (like luminescent ink or pattern printed on said document, luminescent security thread or strip, for example) operable to glow with a specific color luminescence under appropriate UV light illumination. The invention further describes a method for identifying a denomination of a banknote having a test zone including a marking operable to glow with a specific color luminescence according to the denomination under appropriate UV light illumination.