In a new study, scientists have created a pattern that is so complex that it is impossible to copy or fake patterns that will effectively combat counterfeiters. The key to these patterns is a two-step verification system that integrates micropatterns with the basic principles of the echo wall, according to researchers at Tsukuba University in Japan.
Researchers at Tsukuba University designed the micropattern sisopa to be used for authentication and anti-counterfeiting
In a traditional echo wall building (also known as a whisper cloister), if two large concave discs are placed at two ends of a long corridor, the voice of the person next to the other can clearly be heard when someone whispers to one of the discs. Some huge rooms can also have echo walls, such as St Paul’s Cathedral in London. Echo wall effects have also occurred in the lower halls of New York City’s Central Station. All of these spaces have something in common: they are round, and the surface reflects sound to unexpected places. However, in developing this unlikely pattern, the researchers used light waves reflected in the microscopic chamber, rather than the sound waves in the giant room.
Researchers at Tsukuba University designed the micropattern sisopa to be used for authentication and anti-counterfeiting. Similar safety measures are usually embedded in the product during production. In the study, the researchers embedded the phenomenon generated by light waves into a microscopic image.
In an article published May 6 in Materials Horizons, a leading international journal of materials, researchers describe the process of creating patterns. They embedded a light-wave fingerprint into a tiny, 1mm wide (about a tenth the size of a keyboard key) of the Mona Lisa. This tiny image contains an average of millions of evenly spaced pixels per square centimeter.
Researchers at The University of Tsukuba in Japan say they have created unique color patterns that cannot be forged on millimeter-sized images.
In each pixel, there are light-wave fingerprints that researchers call “echo wall patterns” (WGM). This is a unique color feature created in a microscopic circular cavity with a reflective surface. Each reflector has a unique shape, including oval, spherical, flat, hemispherical, etc., but always has a reflective circular surface that promotes the echo wall effect.
As with a human fingerprint, no two reflective cavities are exactly the same. In each cavity with a unique shape, researchers at Tsukuba University dropped a microscopic fluorescent dye droplet, which is chemically sensitive to light. After dripping into the dye, the researchers irradiated visible light and ultraviolet light on the dye in a random and unpredictable manner. Light waves reflect in each cavity, just as sound reflects in the gallery, causing a reaction from the dye molecules. Different cavity shapes, combined with unique exposure patterns created when light shines on fluorescent dyes, create a unique color feature in each pixel.
“This creates a complex, non-counterfeiting color pattern,” senior study author Yohei Yamamoto said in a statement from Tsukuba University. “The final step in the study was a fingerprint array that covered the entire echo wall pattern with another material, which they were using to create a miniature portrait of the Mona Lisa.
In the near future, this pattern, which contains echo wall-pattern fingerprints, may be used to draw avatars on credit cards and driver’s licenses. Governments and businesses can use the patterns created through this process to combat almost all of the current counterfeiting crimes. The researchers say the technology could be used to ensure privacy and prevent all types of fraud. Perhaps one day, the technology could also be used to identify priceless works of art, such as the Mona Lisa on display at the Louvre in Paris. More uses have yet to be further explored by researchers.