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28 Years Manufacturing And Export Experience On Money Handling Equipments
Currency authentication is an essential aspect of national financial security, and UV authentication technology is a vital method for currency authentication in money counter machines. This article examines the current development status of UV authentication technology for currency based on patent applications.
Currency authentication is closely related to national financial security and has important research value and extensive application. UV authentication technology is one of the key methods for currency authentication for money counter machines. Based on the patent application for UV authentication technology for currency, this article analyzes the current development status of this technology.
UV authentication technology is based on the fluorescence effect of currency. When UV light is irradiated on certain substances, these substances selectively absorb UV light and emit visible light of different wavelengths and intensities. As genuine and counterfeit currency have different abilities to absorb UV light, the fluorescence/phosphorescence materials that do not emit light can be excited to emit visible light with different wavelengths and intensities. Consequently, currency authenticity can be determined by detecting the reflection/transmission rate of currency under UV light, as well as the fluorescence/phosphorescence intensity, size and color. Unlike fluorescence materials, phosphorescence characteristic materials emit light for a longer period of time after being exposed to UV light, and the decay time constant of the emission can also be detected to distinguish genuine and counterfeit currency. UV authentication technology has been in use for a long time and is still one of the important methods for currency authentication, as mainstream currencies around the world still use various types of fluorescent ink. Patent application is an important aspect of technology implementation, and by analyzing relevant domestic and foreign patent applications, the development and latest trends of this technology can be obtained.
Development status of UV anti-counterfeiting technology
Before 1990, there were relatively few patent applications related to UV anti-counterfeiting technology, all of which were filed in the United States and typically involved detecting the presence of fluorescence. One such patent used an electronic optical sensor to detect fluorescence excited by UV light. Subsequent patent applications applied UV anti-counterfeiting technology to high-speed currency counters, allowing for continuous authentication of banknotes. Due to limitations in sensing technology at the time, detection methods were relatively simple. Meanwhile, research was also being conducted on the fluorescent properties of banknotes, and artificial fibers were added to different areas of banknote paper to give them varying fluorescent characteristics.
Between 1990 and 2000, the core technology in this field was being developed in other countries. As the technology advanced, counterfeiters also continued to improve their methods, making it difficult to authenticate banknotes using only fluorescence detection or measurement. A patent was granted for a technique that simultaneously measures UV reflectivity and fluorescence intensity, thereby increasing the accuracy of authentication. Compared to fluorescence characteristics, phosphorescence characteristics not only involve excitation and emission spectra, but also the decay time of emitted light, so some have adopted the approach of adding phosphorescent materials to improve the anti-counterfeiting capabilities of valuable securities. Banknotes are checked for the visible light emitted by phosphorescent materials when exposed to UV light. There have also been patent applications for improvements in banknote paper, such as one that describes a method of producing fluorescent paper with strong color intensity under UV light. In terms of UV light sources, LEDs have been used to replace UV lamps in order to reduce size and minimize interference from other spectra. During this period, technology was also developed for using image capture devices to obtain fluorescence patterns excited by UV light for authentication purposes.
After 2000, the number of patent applications related to ultraviolet (UV) anti-counterfeiting steadily increased, with continuous research in detection devices, fluorescence characteristics, and detection methods. For detection devices, one patent introduced a UV reflection filter, which reflects the light emitted by the UV light source to form light with an orthogonal axis to the transport path of paper, solving the problem of uneven fluorescence caused by insufficient UV irradiation when the currency is wrinkled or folded within the necessary range of the currency. In terms of fluorescence characteristics research, a fluorescence marker that can be distinguished by two types of light was provided, appearing black under visible light and red fluorescence under UV light, including at least two phosphorescent materials in the security marking, requiring excitation by different wavelengths of spectra to increase the identification accuracy. For detection methods, a US patent application used a photodiode to detect the transmission light of the UV and the fluorescence emitted by the currency under UV excitation, further comparing the UV transmittance of genuine and fake currency, controlling the excitation light source to turn on and off to obtain fluorescence and phosphorescence information, and determining whether the fluorescence and phosphorescence information matches the inherent characteristics of the securities through data processing. Additionally, research on counterfeit detection using UV reflection/transmission images of currency is also underway, with a powerful patent for obtaining currency fluorescence reflection images for identification and domestically proposed methods using fluorescence images for technical identification through image matching based on pixels.
Conclusion
Through analysis of patent applications in the field of ultraviolet anti-counterfeiting, it can be found that ultraviolet anti-counterfeiting technology has been applied to banknote anti-counterfeiting as early as before 1990, and it is still one of the important anti-counterfeiting methods. The detection method of ultraviolet anti-counterfeiting technology has developed from early single detection of fluorescence presence or fluorescence intensity, to multiple detection methods, such as analyzing the ultraviolet reflection/transmission image of banknotes, analyzing the light emitted from anti-Stokes materials, etc. At the same time, corresponding detection devices and ink properties have also been continuously improved.
