Powerful Potential

Printed electronics are still trying to move from potential to production

When it comes to printed electronics, the word of the year—indeed of the decade—has been “potential.” The idea of cheap, abundant printed electronics has been around about as long as the idea of “ubiquitous computing” and the “Internet of Things”—the idea that every object around you will contain components that connect it to the vast electronic infrastructure of our work and personal lives. Yet, something happened along the way to realizing this dream. Or, perhaps, something didn’t happen.

Like the ubiquitous radio-frequency identification (RFID) tags that were also touted a decade ago, the market and technology for printed electronics failed to converge into anything beyond a great deal of possibility. It is fitting, then, that when research group IDTechEx came out with a new report on printed electronics, it projected the global 2012 market at $9.4 billion. However, that projection is for printed and “potentially printed” electronics.

There’s that word again. Potential. IDTechEx says the number includes electronics that are “moving toward being printed.”

“It is indeed hard to forecast markets that do not currently exist,” admitted Harry Igbenehi, a technology analyst with IDTechEx. “Printed electronics are being developed not only to replace existing products but to help realize new ones. That is why it is important to talk about potential markets, because products are being enabled that are not yet around.”

For example, Igbenehi said, Samsung is a leader in organic-light-emitting diode (OLED) technology, and is planning the release of a new generation of 40" to 50" OLED TVs in the next couple of years. Plus, it is also “very interested in pushing forward printing technologies for OLED displays, especially as we’re moving toward larger displays. We are talking about ‘potential market’ because the leaders in the technologies are working toward making that potential market a reality.”

That’s a familiar story line to Lawrence Gasman, principal analyst for the research group NanoMarkets LLC, Glen Allen, Va., which has also researched printed electronics. Back in 2008, General Electric’s research arm announced it had developed a roll-to-roll manufacturing process for OLED lighting devices that would begin volume production in 2010. “They went seriously quiet in 2011,” Gasman said.

Trial and error

So, while researchers and companies developing printed electronics remain optimistic about its future, and are working diligently to meet technological and market challenges, the industry’s future is still hypothetical.

A plastic electronics concept developed by the VTT Technical Research Centre of Finland that combines printed electronics and film overmolding. Image courtesy VTT Technical Research Centre of Finland.

That said, several elements are coming together that hold promise for making the dream of cheap and fast printed electronics a reality. There is a melding of different disciplines from the worlds of electronics and printing that are only now beginning to speak the same language, and a move toward developing standards on how industry members will work together.

Part of that process involves trial and error, trying out different printing methods and prototypes to see what works and what doesn’t. That is where the Center for the Advancement of Printed Electronics (CAPE) at Western Michigan University comes in. The goal of the center’s pilot plant is to perfect microgravure printing using the MicroStar MicroEngraving system developed by Ohio (Miamisburg) Gravure Technologies Inc. With this system, the R&D effort is focused on printing features 50µm and smaller, which would then enable the process to compete with older photo-lithography methods.

Establishing reachable goals, and the materials needed to achieve them, is an important step toward printing active devices rather than simple wires, resistors or other passive devices, according to Margaret Joyce, the CAPE’s director.

Said Joyce: “Our goal within the next 2 years is to be able to define material sets and say [to someone], ‘If you want to do a dielectric or if you want to do semiconductor materials, these are the properties those materials must have in order to print them at sub-50µm. And if you have this cell geometry, this is how you have to design [the electronics]. These are the imprinting specifications required for that design to get the performance ability for that device.’ ”

In other words, research centers like CAPE are establishing the infrastructure required for new printed electronic applications. For example, consider those not-quite-ubiquitous RFID tags. RFID antennas are being printed, Joyce said, but not the transistors. Until they, too, can be printed reliably and at high speeds, the dream of printing RFID tags like bar codes on packaging will not be realized.

So what are the best materials for printed electronics? Joyce pointed to a materials registry that CAPE built in partnership with the FlexTech Alliance, an association focused on the electronic display and flexible printed electronics supply chain. Plug in the application and up pops the materials needed and their properties. (The registry can be found at www.wmich.edu/engineer/cape/registry.php.)

Standards needed

After debates over materials and printing processes are eventually settled, there is still one more important piece of infrastructure required to create a viable printed electronics industry: standards. That’s where Daniel Gamota comes in. He is president of Printovate Technologies Inc., Palatine, Ill., which provides design-for-manufacturing and new-product-introduction services to industrial customers. He’s pushing for printed electronics standards through his involvement with IPC, an association for printed circuit board and electronics manufacturing service companies. “We’ve taken distinct industries and groups of subject-matter experts and engineers and brought them together under one umbrella, which is IPC,” Gamota said.

For example, one big challenge is creating a transparent, protective layer for printed electronics. IDTechEx’s Igbenehi noted that for flexible displays such as OLEDs, organic materials are very sensitive to water and moisture. There is a need for low-cost, high-barrier, flexible films that can compete on price with glass before cost-effective, bendable displays can be mass-produced.

Gamota’s group is developing standards for the mechanical, electrical and optical properties required to produce these barrier films.

OLED ahead

One of the key markets for printed electronics is OLED displays. According to IDTechEx, there will be a $4 billion market for OLED displays in 2012, driven by the need to differentiate and add value to smartphones, with Samsung leading the way. Additionally, companies like Samsung and LG Electronics plan to roll out OLED TVs in 2013 or 2014.

Western Michigan University’s Accupress (top) with a microgravure-engraved cylinder (above). The press can print on flexible and rigid materials. Maximum print area is 300mm × 300mm. It is equipped with 3-axis registration control and a camera system to enable multilayer printing of electronics. Image courtesy Western Michigan University.

Companies like Pittsburgh-based Plextronics Inc. are on the bleeding edge of this market. Mary Boone, director of the company’s inks business, said its first OLED products will be manufactured using the tried-and-true, but wasteful, vapor-deposition process. However, the company is working on solution processing for the next generation of OLED products, and it wants to be ready to supply the printable inks.

Currently, Plextronics focuses on conductive polymers that work as a whole injection layer that can be placed between the glass and the emissive (light) layer. It is a piece of next-generation OLED technology that will be printed. Where the technology differs from traditional inkjet printing is that it not only prints color, but can give the film properties such as power and light. Plextronics’ current partners in the project include U.K.-based Cambridge Display Technology Ltd. and Universal Display Corp., Ewing, N.J.

Solution processing is said to be better and cheaper because vapor deposition wastes much of the material. With solution processing, 80 to 90 percent of the material is used. Solution processing has the potential to save millions, and perhaps billions, of dollars in the upfront cost of building a new manufacturing line, Boone said.

Plextronics’ technology is another step along the way toward ubiquitous, bendable computer displays. “To get to these really low-cost, disposable printed electronics on flexible substrates, we must have low-cost substrates that have barrier properties and/or materials with improved stability,” Boone said. “There’s definitely a winning value proposition there. It’s just a matter of when the technologies will get to that point so we can bring those products to market.”

Plextronics’ R&D facility demonstrates small-scale manufacturing of its inks. Image courtesy Plextronics.

Drawing the details

While Plextronics focuses on printing smart materials, SonoPlot Inc., Middleton, Wis., is developing another area of the printed electronics infrastructure—a machine that can do the high-resolution drawing of different materials onto flexible substrates. Everything from carbon nanotubes to nanometallic silver to DNA can be drawn using SonoPlot’s MicroPlotter instrument, according to the company. The product was initially developed for biological micro-arrays, but the budding printed electronics industry soon got wind of what SonoPlot was doing.

“As we took the instruments out to trade shows, people would come up to us and ask about a whole range of materials other than traditional aqueous biological materials,” said SonoPlot CEO Glen Donald. “Could we print them? Could we try printing some of their material on their substrate? We got more customer interest and demand for printed electronics applications, so much so that it now represents, by far, the majority of our activity.”

The product fits the current state of the industry, since there has yet to be the long-predicted massive scale-up of printed electronics manufacturing. Companies can use MicroPlotter to move forward with experiments using different materials and applications. And, Donald said, they will hopefully grow with the industry.

“Our goal is to take it from the research space into the production environment,” he said.

More than just potential

A great many things need to happen before that “production environment” can be scaled up. As NanoMarkets’ Gasman said, it’s one thing to present some amazing printed electronic gadgets at trade shows, but another to produce them in quantities and at prices that will interest the larger market.

However, in the case of RFID, Igbenehi said the main problem is not the market but technology scale-up. “Printing some 1,000 to 1,500 transistors for an RFID circuit at speed and getting high yield is the biggest challenge,” he said. For OLEDs, a cheap, flexible coating that can replace glass is key to its scale-up.

Which printing technology is best

"It depends on what you are printing,” Igbenehi said. “Some devices, such as transistors, need very high resolution, so screen printing is not suitable. Others need lower resolution … so screen printing is preferred. Materials are tailored to printing types. Inkjet is best for smaller devices produced in smaller batches, because details can be more easily modified from device to device. And roll-to-roll is best for high-volume manufacturing.”

Gravure-printed electronics, such as the microgravure technology under development at Western Michigan University, may blow everything else away in terms of speed. “But, in reality, the volumes of printed devices made are not sufficient yet to require the highest-throughput printing methods,” Igbenehi said.

This still leaves the printed electronics space where we began—with a great deal of potential. However, Igbenehi said, examining the potential of this market is not merely an academic exercise. Something could pop up that could take everybody by surprise.

“The market for e-readers is a good example,” Igbenehi said. “Several years ago, e-readers didn’t even exist. Now Kindles are one of the most successful gadgets. Printed electronics enabled that technology, which is now ubiquitous.”

So, from where IDTechEx stands, all the development work under way to create an industry—from experimentation with printing methods and materials to standardization—is preparation for a potential explosion in real opportunity. µ

Contributors

Center for the Advancement of Printed Electronics
(269) 276-3514
www.wmich.edu/engineer/cape

IDTechEx Ltd.
(617) 577-7890
www.idtechex.com

NanoMarkets LLC
(804) 270-1718
www.nanomarkets.net

Plextronics Inc.
(412) 423-2030
www.plextronics.com

Printovate Technologies Inc.
(847) 962-3106
www.printovatetech.com

SonoPlot Inc.
(608) 824-9311
www.sonoplot.com