Communications of the ACM
Flexible Displays Enter the Picture
After decades of research and false starts, manufacturers are introducing actual products featuring flexible displays.
Credit: Samsung
"Small, thin, and sleek" has long been the mantra for designing smartphones, smartwatches, tablets and laptops. A focus on usability—essentially making devices easier to carry and use—has driven enormous advances in form factors. Yet, one thing has essentially stayed the same: virtually all computing devices remain rigid. "As a wearable, they don't conform particularly well to the way humans move and would like to use devices," says Gregory Raupp, Foundation Professor of Chemical Engineering and founding director of the Flexible Display Center at Arizona State University.
It's a challenge that has vexed researchers, who have struggled to develop electronic displays that can bend, fold, flex, and roll—while containing batteries, circuits, and other components. Ultimately, every advance and breakthrough has led to the same dead end: a display that cannot stand up to the rigors of everyday use. "Building devices that work and survive in the real world is extraordinarily difficult," says William Stofega, program director for Mobile Device Technology and Trends at International Data Corporation (IDC).
However, it appears that situation is about to change. After decades of research and false starts, manufacturers are introducing actual products with flexible displays.
Royole Corp., a company founded by engineering graduates of Stanford and Tsinghua universities, recently unveiled a smartphone with a flexible screen that allows the device to be folded like a billfold; the product has been available in China and the U.S. since December 2018.
Meanwhile, Samsung has announced it will introduce a smartphone with a flexible display this year. Others are incorporating flexible designs into products as well.
Says Vladimir Bulovic, a professor of electrical engineering at the Massachusetts Institute of Technology (MIT) and director of MIT.nano (the university's effort to advance nanotechnology), "Flexible formats can be applied to many devices."
Bend, Don't Break
The idea of incorporating flexible displays into electronics dates back more than 40 years. In 1974, Xerox developed electronic paper—the company dubbed it "Gyricon"—at its research facility in Palo Alto, CA. After the turn of the century, other companies—including Sony, Nokia and HP—began to explore the idea of producing flexible e-paper and other display technologies. However, engineers couldn't build the technology to withstand real-world conditions; at least, not while achieving a price point that made it viable for commercial production.
Over the last few years, the prospect of flexible displays has become more real. New materials, better production methods, and other advances in technology have raised hopes of viable products. The underlying OLED technology is now at a point where it works well, but encasing the displays in plastic or ultra-thin glass remains a challenge. Samsung's foldable smartphone, for example, incorporates an interior screen that uses a composite polymer transparent material to encase a bendable AMOLED display. The manufacturer claims the smartphone, which it has named the Samsung Infinity Flex Display, can open and close at least 300,000 times without suffering damage.
Other companies are also moving flexible products from the research lab to production. Royole's FlexPai device resembles a tablet more than a smartphone; it features a 7.8-inch 1440p AMOLED display supported by a hinge that allows the device to flex to almost any desired angle. Royole also has announced a partnership with Airbus to produce flexible electronics for aircraft, and plans to produce clothing with display technology.
ASU's Raupp points out that the technology could impact fitness trackers, smart watches, Internet of Things devices, consumer electronics, and industrial control systems. For example, researchers at ASU are developing a flexible mobile X-ray device that could conform to the human body, capture images, and then display them on a flexible readout. "There is an amazing array of possibilities," he says.
The Big Picture
Despite growing excitement over flexible display technology, some questions remain. For one, manufacturers face challenges in producing flexible devices that match today's watches, smartphones, tablets, and laptops in terms of performance and quality. As Raupp puts it, "How do you deploy that flimsy, plastic display into a product that will be robust and that the user won't damage by flexing it too much?" Incorporating batteries and other electronic components ratchets up the challenge.
For another, "No one has attempted to produce flexible displays on a larger scale. Mass production creates distinct difficulties," Stofega says. This includes obtaining necessary materials and components on a scale required for commercial production while maintaining quality standards. Today, many device manufacturers face supply chain constraints that inhibit production.
Finally, and perhaps most importantly, there's a question of whether the public will desire flexible devices to replace today's phones, tablets, and laptops. "The social response to this technology is a complete unknown," Bulovic says.
Nevertheless, the drive toward flexible displays and other electronics marches on. Stofega says the technology will likely make inroads in the months and years ahead, but not necessarily in ways people anticipate or predict. Some things, like smart watches, fitness trackers, and clothing, seem like a natural fit for the technology, while others such as tablets, smartphones, and large fold-up OLED TVs that a person could easily hang on a wall also seem likely.
Concludes Raupp, "We're now at a point where the manufacturing problems have largely been overcome and it is a question of innovating and integrating flexible displays in new, unique, and novel ways. It's up to the design community to transform ideas into reality."
Samuel Greengard is an author and journalist based in West Linn, OR, USA.
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