Authenticity Detection Using Wavelength Selective Filters
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing authenticity determination apparatuses face challenges in accurately detecting latent-image marks on paper sheets due to wavelength overlap between excitation light and the light emitted from anti-counterfeit ink, leading to insufficient detection accuracy and increased production costs when using specialized light sources.
Innovation Solution
The apparatus employs a light-emitting unit with a short pass filter to block wavelengths longer than the excitation light and a light-receiving unit with a long pass filter to block wavelengths shorter than the emitted light, allowing only the fluorescence from anti-counterfeit ink to be detected, thereby improving accuracy and reducing production costs by using a commonly available light source.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a light source emitting a single wavelength is used to avoid wavelength overlap, then detection accuracy is improved, but production cost increases
Solution Approach 1:
The patent introduces wavelength selective filters (first blocking unit and second blocking unit) as intermediary components between the light source and the detection system. These filters act as mediators that separate the excitation light from the emitted light by wavelength, allowing a cost-effective broadband light source to be used while achieving single-wavelength detection accuracy. The first blocking unit blocks wavelengths longer than the excitation light, and the second blocking unit blocks wavelengths shorter than the emitted light, effectively isolating the fluorescence signal.
2Ease of manufacture
If a broadband light source is used to reduce cost, then production cost decreases, but detection accuracy deteriorates due to wavelength overlap
Solution Approach 1:
The patent extracts the desired wavelength component from the broadband light source by using wavelength selective filters. The first blocking unit extracts and blocks the excitation light wavelengths that would interfere with detection, while the second blocking unit extracts and blocks shorter wavelengths. This extraction of unwanted wavelength components allows the use of inexpensive broadband light sources while maintaining high detection accuracy by isolating only the fluorescence emission wavelengths.
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 configuration enhances the accuracy of authenticity determination while keeping production costs low by isolating the fluorescence emission from the anti-counterfeit ink and using a standard light source.
Implementation Method 1
When irradiated with an excitation light of a predetermined wavelength (for example, a visible light or an infrared light), such phosphor-containing ink emits an invisible light (for example, an infrared light) of a different wavelength from that of the excitation light.
Data Source
AI summary
An apparatus for determining the authenticity includes a light-emitting unit that emits a light including the first wavelength to the paper sheet; a first blocking unit that is arranged between the light-emitting unit and the paper sheet, and blocks off a light of a wavelength longer than the first wavelength; a light-receiving unit that receives a light including a second wavelength emitted from the paper sheet; a second blocking unit that is arranged between the light-receiving unit and the paper sheet, and blocks off a light of a wavelength shorter than the second wavelength. Finally, an authenticity determining unit determines an authenticity of the paper sheet based on the light received by the light-receiving unit.