□Christine

　　During the Beijing Winter Olympics, the mascot "Bing Dun Dun" successfully attracted a large number of fans.

And there is a hidden "Bing Dun Dun" that also attracts many people's attention. That is the commemorative banknote for the 2022 Beijing Winter Olympics. One of its anti-counterfeiting technologies - through the transmitted light source, the surface of the banknote can clearly see a snowboarder. "Bing pier".

　　"Bingdundun" anti-counterfeiting is very popular

　　As a special Chinese business card, the 2022 Beijing Winter Olympics commemorative banknotes show the world the smart and delicate beauty of China.

In its special design, the hidden "Bing Dun Dun" pattern watermark is obviously a part that is deeply loved by consumers.

　　The design on the banknote is a snowboard "Bingdundun" with the Great Wall of China in the background.

The commemorative banknote adopts a new nano-optical microstructure, which also enables the banknote surface to show structural color changes with dynamic characteristics. From vertical, inclined and other directions, the dynamic and agile holographic anti-counterfeiting "Bing Dun Dun" can be observed. beauty of.

At present, "one pier is hard to find". Many people believe that having a commemorative banknote can also realize the dream of "one pier for every household". Therefore, commemorative banknotes with such special anti-counterfeiting technology are also very popular.

　　In addition, the glorious light-changing music score pattern on the front and the snowflake pattern on the back are all colorful, and the commemorative banknote is also a rare colored commemorative coin.

　　Plastic banknote making technology is difficult to imitate

　　In fact, the most noteworthy thing about the Beijing Winter Olympics commemorative banknotes is its plastic banknote production technology.

But only the ice sports commemorative banknotes are plastic banknotes, and the snow sports commemorative banknotes are still paper banknotes.

　　Plastic banknotes are made of polymer film as the base film, and are printed with a variety of anti-counterfeiting technologies.

Therefore, compared with traditional paper banknotes, plastic banknotes are more difficult to counterfeit and imitate, which is the main direction of world currency development.

　　It is understood that although more than 30 countries in the world have used plastic banknotes, only 3 countries have the ability to develop and produce plastic banknote substrates-except my country, only Australia and the United Kingdom.

Because the production process of plastic banknotes is quite difficult: the first is to have a qualified plastic base film; the second is coating, that is, the plastic substrate is treated like paper before the ink can be printed; the third process is printing; the last process It is anti-counterfeiting treatment.

Among them, the manufacturing technology of the base film is extremely demanding, and this kind of plastic film has always been technically difficult to balance the rigidity and flexibility.

　　my country began to study its own technology for making plastic banknotes many years ago.

With the support of many parties, the Institute of Chemistry, Chinese Academy of Sciences, based on years of basic research accumulation, has continued to carry out key core technologies for the base film of plastic banknotes, and has achieved stable production of the base film of plastic banknotes.

　　Nano-optical microstructure is a breakthrough

　　The film technology that can be used for printing realizes the printing of plastic banknotes. In addition to showing an ice-like crystal clear beauty, the commemorative banknotes are supported by multiple anti-counterfeiting technologies to achieve both anti-counterfeiting and beauty.

　　However, the core technology of the optical window part of the Winter Olympics commemorative banknotes is also a highlight.

It uses a nano-optical microstructure technology, which is internationally known as "ZERO TO ZERO" technology, also known as zero-error precision nesting etching technology.

This may be the first large-scale application of this technology in China, which is an important breakthrough.

　　There is a part of the optical microstructure on the plastic banknote, and its thickness is said to be equivalent to 1‰ of the diameter of a hair, but it integrates diffractive optics, refractive optics, Motion optics, vacuum film optics, and waveguide optics technologies, using 3D nanolithography, zero The creation of zero-etching, multi-frequency micro-nano structure superposition and other process technologies can be called a landmark project of ink-free optical printing.

　　If you look closely, you can see that the independent "snowflakes" in the pattern are floating in the window, and the fine light diffraction lines run through the window. These "snowflakes" and lines and the nano-optical microstructure are strictly and precisely set.

　　There are also skills in saving commemorative banknotes

　　Commemorative banknotes are born with the support of these high-end technologies, and naturally they also need to be preserved so that they will not be easily damaged.

Experts suggest that commemorative banknotes should be stored in a dry room temperature environment, and avoid long-term storage in a high humidity and high heat environment.

　　In addition, commemorative banknotes should avoid contact with corrosive substances such as strong acids and alkalis, avoid contact with organic solvents, it is best to avoid direct sunlight or other strong light sources for a long time, avoid scratching with sharp objects, and avoid strong wrinkling and rubbing.

　　Of course, since it's a commemorative note, you probably won't just take it to the supermarket to buy Coke.