After the birth of conductive ink, ordinary ink-jet printer can finish the production of flexible circuit board in a few minutes, make flexible wearable multiplied improve equipment research and development speed and cost.
In this era of almost every family have a tablet, what's the use of buy an inkjet printer? Print working file, help children prepare for materials, occasionally to play two photos, could eventually just landing ash. Or, according to researchers at the university of several ideas, it can also become an important part of the personalized production.
From the Georgia institute of technology, university of Tokyo, and Microsoft research (37.4, 0.32, 0.86%) of a number of researchers recently found a rapid development technology of the electronic equipment, can be directly through the home inkjet printers make circuit board.
With low-cost 3 d printers, and laser cutting technology made the shell, this technology is expected to further reduce the hardware business development threshold, help entrepreneurs quickly practical idea, improving design, eventually bring innovative smart toys or wearable devices.
Just open a computer or mobile phone, you will see one or more blocks of PCB circuit boards. PCB is green, but are often treated to red, blue, black, or designers want any other color. If the processor's power supply, signal transmission between components, all through the small board with wire to finish. They are often in large batch production by the professional equipment in the workshop.
Before the start of mass production, developers need to make a few pieces of circuit boards to test design, and then modify the design according to the test result. This process is known as proofing or prototyping.
University experiment and product research and development initial period common bread plate proofing. User interface in a densely whiteboard insert element, such as the electrical wiring, sensors, resistance simulation in the end the performance of electronic products. Changes on the bread board design is very convenient, but its large size, and reliability and performance and finished goods discrepancy, sooner or later, developers have to pull on the PCB printed circuit board.
Rapid production circuit board, in order to help entrepreneurs and researchers have company provides online submission design, production to complete, quick to the user's service. But the production pattern at least need more than a day just may get a circuit board, seriously slow down the speed of product development, design requires twice a week.
With as a decline in the cost of 3 d printers, and laser cutting machine, hardware entrepreneurs have been able to in the day time to try a variety of different casing design. PCB long processing cycle has become entrepreneurial hardware product design at the beginning of a short board.
"We think it is a method of rapid proofing, custom PCB," Georgia institute of technology, interactive computer college professor Gregory Po's (Gregory Abowd) argues that this technology should be faster and cheaper, "too cheap to anyone who wants to practice can afford."
The latest breakthrough in materials science make it possible for Po's idea. Mitsubishi researchers have invented a Wu Xuanfang tree don't need high temperature treatment, after drying after a chemical reaction to produce electrical conductivity of conductive ink. It will dissolve the diameter less than 0.1 micron silver nanoparticles in special solvent containing polymer latex, the ink dry after a few seconds will produce electrical conductivity.
To make sure that the conductive ink can smoothly from the printer nozzle, mitsubishi to ink viscosity, surface tension, volatile and particle size are optimized, mass production version per 100 ml price 100 yen. Circuits used for circuit board printing, 1 mm wide, on average, five cents per meter, the cost is not high.
The researchers tested this in much money on home inkjet printer ink conductors, found out the ink quantity larger inkjet printer can normal use, the cheapest one less than $100. The researchers used a needle to conductive ink injection clean empty cartridges. In order to avoid affect conductivity floater with ink and injection process need to use the disposable filter tube.
Lower the resistance of the conductive ink to paper, but also to prevent the spread of ink to ensure that the electrical conductivity. Surface treatment is required, it was found that glossy photo paper, transparent PET plastic film can meet the demand of printed circuit. These materials are soft, flexible, suitable for flexible wearable electronic equipment research and development. This is the general PCB board can't provide customized service.
Print circuit itself does not need special software, developers as long as the design circuit diagram into a bitmap images can be used. But the thickness of the printed circuit cannot too thin, too thin will not be able to ensure that electrical conductivity. So patterns of choice when printing photos, and the printer will be green, red and yellow area of the conductor jumbled together black ink, the ink is higher than that using black ink cartridge text mode.
The researchers found that ink-jet printing of the resistance of the circuit board will change with the passage of time, after 7 months will increase 15%. This is the result of silver nanoparticles after oxidation, long-term use will affect the circuit board. Solution is simple, direct pressure on printed circuit boards with a family photo encapsulation machine in a layer of thin film can effectively prevent oxidation.
Circuit board just basis, after the completion of the printing of the next step is to install the processor components, resistors, sensors. Traditional PCB components are fixed up, by means of welding is very strong. But welding need at least 180 ℃ high temperature, damage and influence of congealed circuit boards at the bottom of the paper.
Researchers found the solution is through the silver conductive adhesive element, this is the strongest installation method. In the oven at 65 ℃, conductive silver glue can be fixed components in ten minutes. Production of conductive and 3 m double-sided adhesive, also can be used for fixed components.
In addition to the circuit board itself, the developer may also directly inkjet print out simple antenna, even a touch sensor. On children's toys equipped with touch button, for example, after feeling touch play music. This kind of antenna and sensor printing costs, often only several cents.
Electronic circuit board production is a huge market, output value of 9.4 billion dollars last year. Laboratory (xerox PARC) also conducted a similar attempt, this year launched a called Silver Bullet (Silver Bullet) of conductive ink, can be directly printed circuit on the plastic sheet. Print the finished plastic board with 150 ℃ high temperature heating hours is needed to install components. In addition from Fuji xerox's new material need to use company's industrial printers, usually cost more than $50000.
Compared to xerox's special inkjet printing equipment, Georgia institute of technology solutions only $300, the printing speed is faster.
In 1988, xerox laboratory chief scientist Mark Weiser (Mark Weiser) put forward the concept of ubiquitous computing, a large number of wearable devices, tablet and the birth of large-screen interactive devices will turn into computer users all around. Weiser's prophecy has been gradually become a reality.
Involved in the project at the university of Tokyo, an assistant professor at sichuan harakosan believe that their research is the important step to pervasive computing. Pervasive computing conference this year, sichuan harakosan published a paper detailed instant ink-jet printing circuit technology and the details of the prospects. In the paper, he writes, "all of the materials used in the study is on the market can buy goods directly, you can directly to experiment at home. This method can be at very low cost printed circuit board, sensors, and antenna, bring a lot of new opportunities."
