![]() Many people and organizations use UV markers to protect and hide sensitive messages from the public. Other applications include retailers marking their items to identify customers who might exchange or return items that were not originally bought from their stores. Moreover, various countries use UV markers to create marks on state issued driving licenses and identity cards to ensure they are authentic. Credit cards are marked with a particular logo or the card type. For example, in the state of Illinois, the lottery tickets are stamped with UV-invisible ink to indicate authenticity. UV markers are also widely used on credit cards or lottery tickets for authentication, to help discourage counterfeiting. It is also sometimes used in identifying whether a document is an original or a copy. Applications Security and authentication Ĭommercially available UV markers are used to mark things for security purposes, such as to check for counterfeit money and mark property in the event of theft for the purpose of identifying ownership. In some cases, people can also use photocopiers to develop UV-visible ink messages, because the scanning head of the machine emits UV light. When the black light falls upon UV-visible ink, it makes the ink fluoresce so that it emits visible light, making the message readable by human eyes. Therefore, UV LEDs are claimed to be completely safe, causing no damage to eyes nor risks of skin cancer. The lamps used have very narrow bandwidth, compared to regular fluorescent black lights. The near-ultraviolet radiant energy is also called black light with a wavelength of 380 nm, which falls just outside the visible spectrum. UV LEDs emitting near-ultraviolet light are used to read messages written by UV markers. All three types contain acrylic monomers which contain a diluent and a photoinitiator to participate in the curing reaction and to respond to UV radiation. There are different types of UV-visible ink: opaque, semi-opaque, and translucent. Modern UV-visible ink uses a fluorescent component derived from materials that glow when exposed to an ultraviolet light. The main components in improvised inks have included dilute laundry detergent, body fluids, tonic water, and vitamin B-12 dissolved in vinegar. In the past, the ink used in UV markers has been made from various things such as lemon juice, vinegar, diluted blood, or even urine.
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