Sheet Recognition Using UV-Excited Visible and IR Photoluminescence
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Solution Overview
Problem
Existing security elements using photoluminescent compounds lack mechanical recognition capabilities, necessitating improved methods for authenticating sheets such as banknotes.
Innovation Solution
A sheet recognition unit that includes a light source emitting ultraviolet light, a light sensor receiving photoluminescence, and processing circuitry to recognize sheets based on visible and infrared photoluminescence emission amounts within allowable ranges using reference data, with optional spectral overlap correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If photoluminescent compounds are used as security elements, then authentication capability is improved, but mechanical recognition capability deteriorates
Solution Approach 1:
The patent segments the photoluminescence detection into multiple wavelength bands (visible and infrared) with dedicated light sensors for each band. This segmentation enables precise measurement of different photoluminescence emissions, improving authentication capability while maintaining system manageability
Solution Approach 2:
The patent replaces mechanical recognition methods with optical detection systems that measure photoluminescence emissions. The light sensors detect photoluminescence signals and convert them to electrical signals, enabling non-contact, high-precision authentication without mechanical intervention
2Measurement precision
If multiple wavelength bands are detected, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent combines multiple light sensors capable of detecting different wavelength bands into a single integrated detection unit. The processing circuitry processes signals from all sensors uniformly, merging the detection functions while maintaining the ability to distinguish between visible and infrared photoluminescence emissions
Solution Approach 2:
The light sensors are designed with multi-functionality to detect both visible and infrared photoluminescence emissions. The processing circuitry performs multiple functions including signal amplification, analog-to-digital conversion, and spectral analysis, reducing the need for separate specialized components
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
Enables high-security authentication of sheets by accurately distinguishing genuine from counterfeit items through precise measurement of photoluminescence emissions.
Implementation Method 1
a light source capable of emitting at least ultraviolet light to a sheet to be recognized
Implementation Method 2
a light sensor that receives photoluminescence emitted from the sheet to be recognized, the sheet being irradiated with the ultraviolet light, and outputs a photoluminescence detection signal
Data Source
AI summary
Provided is a sheet recognition unit including a light source capable of emitting at least ultraviolet light to a sheet to be recognized, a light sensor that receives photoluminescence emitted from the sheet to be recognized, the sheet being irradiated with the ultraviolet light, and outputs a photoluminescence detection signal, and a processing circuitry that recognizes the sheet to be recognized using the photoluminescence detection signal output from the light sensor, based on whether a visible photoluminescence emission amount and an infrared photoluminescence emission amount of the sheet to be recognized are within an allowable range with respect to reference data related to a visible photoluminescence emission amount and an infrared photoluminescence emission amount in a genuine sheet.