The crisscross and extremely complex circuit diagrams such as The Picture of the River on the Qingming Festival, the Great Wall, and the U.S. Capitol are presented on transparent films. It is hard to imagine that a circuit diagram can be so artistic.

Have you ever thought of making a personalized computer, a music greeting card or a special circuit board by yourself? Not long ago, the world's first fully automatic liquid metal personal electronic circuit printer developed by the Institute of Physical and Chemical Technology of the Chinese Academy of Sciences may help you realize your dream.

Dancing "Spirit"

In the Laboratory of Cryogenic Biology and Medicine of the Institute of Physical and Chemical Technology of the Chinese Academy of Sciences, the reporter saw that this "new concept" printer was rather "ugly", with a cuboid appearance, and the transparent black plastic material added some spirit to it. However, this guy who is not amazing is actually "pretty".

Beside it, various crisscross and extremely complex circuit diagrams, such as Picture of the River on the Tomb Sweeping Day, the Great Wall, and the U.S. Capitol, are presented on transparent films. It is hard to imagine that a circuit diagram can be so artistic. These exquisite circuit diagrams are all made by him.

"As long as you touch the designed circuit diagram on the computer, it can print the circuit diagram on the transparent film like a dancing 'spirit'. After the metal liquid solidifies or encapsulates, your dream circuit will become a reality." Liu Jing, the director of the laboratory and the inventor of the liquid metal printer, vividly introduced to the reporter of China Science Daily.

It is the dream of the global scientific and industrial circles to realize the direct printing of electronic circuits anytime and anywhere. However, due to the technical bottleneck, most electronic circuit manufacturing can only be carried out in large factories with complete equipment. The invention and appearance of this printer will overturn people's understanding of traditional manufacturing and open a new electronic circuit manufacturing mode.

"As long as several ICs are added to the printed circuit diagrams, they can be used directly after being powered on." Yang Jun, a graduate student of the research group, took a printed palm sized circuit diagram and saw that a few small chips and wires were connected to it, forming a simple FM radio.

Contrary to the time-consuming, consumable and energy consuming characteristics of traditional electronic circuit manufacturing, Liu Jing said that this printer can complete the traditionally cumbersome work in more than ten minutes, making low-cost, fast and personalized electronic circuit manufacturing a reality. Because of this, some basic research achievements related to this printer were recently published in the journal Science Report of Nature Publishing Group.

"Fruits are ripe and well preserved" originates from accumulation

In fact, this is not the first liquid metal printer produced by Liu Jing's research group. A year ago, the team led by Liu Jing created a sensation by inventing a liquid metal inkjet electronic printer that can make circuits on any surface.

"Different from last time, the biggest feature of this machine is full automation. Even people without any electronics experience and even children can control it through a computer." Liu Jing said. This extremely universal and basic electronic manufacturing tool carries the technical innovation accumulation of Liu Jing and others for many years.

Many people who have seen these shiny silver circuit diagrams, which look like a dragon, mistakenly believe that these circuit materials are just ordinary "silver paste", but in fact, the conductivity of these alloy wires is 100 times that of traditional silver paste, and the circuit breaking problem like traditional electronic ink will not occur after bending.

In order to obtain metals that can flow at room temperature and have good adhesion, the research team exhausted various methods, and finally found alloy combinations with gallium as the main component, and used them as "ink" to make circuit boards. As a result, Liu Jing and the research team took the first step in global liquid metal printing. They gave this technology a poetic name - "ink of dreams"; Since then, the liquid metal printer developed has also been called "Dream Ink" printer.

However, new problems follow. How to let the liquid metal with high viscosity and high surface tension flow out of the pen? How to make the metal droplets rolling around adhere firmly to the base material? In this regard, the research group has launched a new round of research. Finally, they solved the above problems through atmospheric extrusion, impact and fluid modification.

To be a "perfect" science

"To make such a machine, we must have a forward-looking vision. Teacher Liu's idea has always been very advanced." Zheng Yi, the first author of the paper and a rather shy graduate student, told the reporter.

In fact, Liu Jing has a definition of "perfect science" in her mind. It has two conditions, namely, to discover new knowledge and create new technology. In his view, frontier research and application practice complement each other. The former is the cornerstone of innovation. Otherwise, such scientific development "will not be vigorous" if we pursue immediate applications only for quick success and instant benefit.

The "Dream Ink" printer is the perfect combination of basic research and application exploration. The industry believes that it has opened the door to the production of personal electronic circuits, completed the process of private circuit customization from scratch, and is a revolutionary technology leading the transformation of the integrated circuit industry.

It can be used in education, scientific research, military and other fields of military and civilian circuit production, and can also let private circuit customization really enter the homes of ordinary people. For example, the wireless ECG measuring device can be printed out to facilitate the measurement of physiological parameters such as ECG signal and bioelectrical impedance. At the same time, it can also promote the development of circuit design, terminal function device manufacturing and other related industries.

Liu Jing said that the research group will further develop new applications, such as developing more liquid metal functional inks and substrate printing materials; Technically, it can realize the lamination printing from single layer board to multi layer board, and even combine P-shape and N-type semiconductor ink materials to print composite all electronic components; The ultimate goal is to realize direct printing of all integrated circuits.