Anti-counterfeiting Security Labels Use Dot-Matrix Hologram and Electron Beam Lithography to Reduce Risk of Forgery

Counterfeiting is a serious problem that can be encountered in everyday life, including banknotes, documents, tickets, and even shopping. The scale and seriousness of this problem are so great that Lithuanian researchers decided to create a new method of producing holographic security labels.

(Photo: Wikimedia Commons/ Newone)

Harnessing the Potential of Holograms

Holograms have been utilized as an anti-counterfeiting tool for quite some time. They can be seen on brand labels, pharmaceutical packaging, and children's toys. In banknotes, holograms are much more difficult to counterfeit than watermarks since they require complex micro and nano technologies that cannot be found in traditional printing houses.

Holograms were originally invented to increase the resolution of electronic microscopy. The use of this technology in preventing forgery started when experts realized that a recorded hologram could be copied mechanically by pressing it into another material. This discovery has led to a substantial expansion in the production of holographic security labels.

Manufacturers make holograms as bright as possible. The visible features, like apparent objects and different colors, do not glow by chance. Manufacturers integrate only specific elements of the brands into the image with various sizes of visible characters. If a random glow is observed, it has a chance of being a fake or a very unsophisticated hologram.

Battle Against Counterfeiting

At Kaunas University of Technology (KTU), researchers tried to enhance protection against forgery by combining two technologically different methods. One of them is a dot-matrix hologram made of tiny dots that refract light.

Barely smaller than a human hair, each dot records a periodic pattern of lines called diffraction grating. This structure causes the light to play visibly to the observer's eye, similar to a CD or DVD technology. However, although the dot-matrix hologram is relatively faster and cheaper, it does not guarantee high protection.

For this reason, the research team used electron beam lithography to expose smaller hologram areas. This advanced technology allows high-resolution counterfeiters to form and is practically inaccessible to potential hologram counterfeiters.

This combination has received international recognition by the US Patent and Trademark Office and the Japanese Patent Office. The holographic label technologies developed by KTU experts are already used widely for metrological verification on product packaging, car license plates, tickets, and diplomas.

Dr. Viktoras Grigaliūnas, a researcher from KTU, led the research team. Their findings are discussed in the paper "Fabrication method of holographic security label."

One of the new method's inventors, Dr. Tomas Tamulevičius, noted that holograms can also be counterfeited. He encourages consumers to inspect the holographic security labels and remain alert to strengthen the protective measures themselves.

The inventors collaborated with experts from the Faculty of Informatics (IF) at KTU to develop another innovation. They created HoloApp, a digital application for smart devices that enables users to see what the holographic security labels should look like. This allows them to identify if a hologram is forged.