New Technology Easily Identifies Fake Goods

Professor Heon Lee’s team develops anti-counterfeiting technology using nanoimprint

▲ Heon Lee, Professor, Department of Materials Science and Engineering

The research team led by Professor Heon Lee of the Department of Materials Science and Engineering announced the development of anti-counterfeiting technology using nanoimprint.

The team’s anti-counterfeiting technology using nanoimprint enables users to easily distinguish between authentic and counterfeit goods, which are continuously evolving. 

This technology applies a laser on the surface of goods in order to determine their authenticity based on the characteristics of the transmitted or reflected light. Light travels in a straight line in a medium with a constant refractive index, and it is diffracted at the boundary of the two mediums with different refractive indices. The anti-counterfeiting optical diffraction pattern converts the transmitted or reflected light into desired shapes. Phase differences occur within the light passing through the anti-counterfeiting pattern, and the destructive/constructive interference leads to a diffractive image formation. 

If a resist with a different diffractive index is flattened at the top of the anti-counterfeiting optical diffraction pattern, relative phase differences of the transmitted or reflected light are maintained even though the surface may appear flat and identical to the naked eye. Professor Lee’s team used this property to produce an anti-counterfeiting film that is impossible to duplicate. With this technology, it is very easy and affordable to distinguish between authentic and counterfeit goods. 

Nanoimprint technology and a functional resist with dispersed nanoparticles are used to produce the anti-counterfeiting film with optical diffraction patterns. Using a common transparent polymer material such as PC and PET and a functional resist containing nanoparticles, the team succeeded in the low-cost production of an anti-counterfeiting film that is impossible to duplicate.  

The anti-counterfeiting pattern is made from transparent polymer and a functional resist with a different diffraction index is used to flatten the pattern. The anti-counterfeiting film is highly secure as internal patterns of the functional resist cannot be analyzed when decomposed by physical or chemical means.

The anti-counterfeiting film, inserted with an optical diffraction pattern, can be applied to various fields such as money, electronic products, branded goods, and liquor. When applied to packaging, the film can protect the reputation of the brand by preventing counterfeits and adding higher added-value to such goods. 

The optical diffraction pattern can be applied to ID cards, lenses, and bank notes. By experimenting with various materials, the team found that the smile and KU patterns could be clearly observed. An advantage of this technology is that various diffraction patterns can be contained in a small area.  

Since any image is possible, brands can choose to insert their brand name, logo, or even QR codes. The technology is more affordable than the existing techniques and has a high market value due to its wide range of applications. 

While most counterfeits involve branded consumer goods, the counterfeit market has recently expanded to electronic products, cosmetics, and various components. This has caused significant damage to many brands as counterfeits have become so advanced that they are often difficult to distinguish from the authentic products. Most counterfeits follow the design of authentic goods while placing different logos on the item; however, some use the same logo. In the case of electronic products containing lithium batteries, the use of fake batteries can not only weaken performance, but also lead to overheating or explosion. As such, the development of anti-counterfeiting technology is highly desirable and necessary.

Professor Lee said, “The anti-counterfeiting film has a flattened surface and the information is encrypted with an inverse pattern, making it very difficult to duplicate. The technology is expected to have a huge economic impact as it is cost-efficient, suited for mass production, and applicable to all kinds of materials.”

▲ Diffracted image produced from reflected laser. 

This implies that the technology can be applied to all products, regardless of their transparency.

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