More Than TV: The OLED Display Revolution

Super-thin, flexible OLED displays may bring us roll-up tablets, dimming windows, and interactive drawings.

For nearly a decade, advocates of OLED technology have evangelized about the sci-fi-like potential of these ultra-thin, flexible displays: foldable tablets, dimming windows, solar-powered clothing, self-refreshing newspapers a la Minority Report—everything short of a sustained fusion reaction, it seems.

With the unveiling of two new OLED TVs from LG and Samsung, the technology has once again popped up in the public spotlight, as it has periodically for the past few years. This time, however, the technology seems ready for the mainstream.

Samsung's KN55SC9 curved OLED TV.

OLED is so captivating because its potential extends beyond TVs and smartphones. While the OLED TVs recently launched by LG and Samsung are still prohibitively expensive (the cheaper of the two, the Samsung KN55SC9, still costs nearly $9,000), the technology has reached a tipping point. People are grasping the possibilities, and they want to know more.

How Does it Work?

A flexible OLED display. [Wikimedia Commons user meharris]

Unlike LCD and LED TVs, OLED (Organic Light-Emitting Diode) displays do not require a backlight. Instead, light is emitted from individual cells behind each pixel. Each single cell can be turned on or off. Dark parts of the screen are “true black,” with tones darker than the inkiest plasma displays. Light parts are much brighter than LCD (including LED) screens. It's truly the best of both worlds. As an added miracle, the displays can be bent or curved—the array of diodes is paper-thin, and there's no backlight.

OLED is so exciting because it's more than just a catalyst for improved color accuracy and contrast ratios—it has the potential to revolutionize display technology. An ultra-thin display that can be bent, warped, or even reeled like a scroll could be the missing link between mobile computing and wearable tech. Heck, with all the possibilities for windows and appliances, it may even revolutionize domestic life—so long as it can be manufactured cheaply.

Why so Expensive?

While small OLED displays have already been used in a number of digital cameras and smartphones—including the Samsung Galaxy S4—it's only very recently that they've started to appear in bigger sizes, like the 55-inch Samsung and LG TVs. What was the holdup?

Well, it turns out that it's very difficult to manufacture a large OLED display without defects. Paul Gagnon, director of global TV research at NPD DisplaySearch told us that fewer than half of all OLEDs manufactured are fit for sale. (By comparison, about 90 percent of LCD displays come off the assembly line ready for stores.) This keeps costs really high—LG's 55-inch curved OLED TV costs $14,999.

But strides are being made. Samsung confirmed to us that they're able to sell their 55-inch curved OLED for significantly less than LG's thanks to "better-than-anticipated yields." That said, $9,000 for a 55-inch TV is still really pricey.

Fewer than half of all OLEDs manufactured are fit for sale, which keeps prices very high.

One California startup called Kateeva is developing a method for printing light-emitting organic compounds onto large sheets for manufacturing, which could help reduce one aspect of OLED manufacturing’s enormous costs. A separate team of researchers from the University of Louisville in Kentucky are building tiny, printable “quantum dots” that could simplify the manufacturing process for OLED lights.

But for many OLED devices, the most fundamental manufacturing issue is with the color filter. Because OLED pixels generate their own light, each one needs its own filter. As you can imagine, this becomes expensive when applied across industrial-scale OLED sheets.

Samsung’s tech bypasses the need for color filters by independently exciting the red, blue, and green sub-pixels that exist within each pixel. Like paint mixed in a bucket, these three tones work together to create all the colors of the rainbow. Boastfully dubbed “True OLED,” this method also creates a more luminescent image since the light doesn't have to pass through a filter. It does require an enormously precise patterning system, though.

Scrollable OLED display
A scrollable OLED display [Wikipedia Commons user "nDevilTV"]

A New Branch on the OLED Tree

If OLED technology desires a life beyond TV screens, it needs to work with the kinds of microdisplays found in augmented reality (AR) glasses, tools, and other kinds of next-generation mobile tech. The RGB OLED technology Samsung uses on its TVs and smartphone prototypes is not practical for these purposes. The red, green, and blue sub-pixels in microdisplay diodes are simply too small to fabricate on this scale. This means OLED displays for watches, glasses, and tools will still require expensive color filters.

With this obstacle in mind, a research team from the Fraunhofer Institution in Germany adopted a manufacturing system called flash-mask-transfer-lithography (FMTL) that locally deposits organic compounds—the electroluminescent light source of OLED devices—onto diode sheets. Because this eliminates the need for a color filter, it allows for a more luminescent microdisplay that is also cheaper to produce.

Samsung Places its Bet

Whether or not the Fraunhofer method takes hold, there is a clear desire to rein in the manufacturing costs of OLED sheets—big or small. Because the demand is so high, such an outcome seems inevitable, which has prompted some interesting concepts for next-generation display technology.

Samsung has been one of the chief backers of OLED technology for mobile devices. Earlier this year, the Korean electronics giant unveiled a prototype OLED smartphone with a screen that curves along the right edge of the handset. It certainly looks cool, and Samsung claims such a feature could allow owners to view tickers or screen calls without removing the device from a jacket.

Samsung showed off a prototype tablet that can be folded into quarters and stored in a pocket.

The company also unveiled an entire brand name devoted to flexible OLED displays, called Youm. These devices use a flexible plastic array that lets displays bend. The most stunning application of this is a prototype tablet that can be folded into quarters. This—the ability to fold a tablet into something you can fit in your pocket—is OLED at its most exciting. Whatever the brand name, such technology could theoretically be applied to anything from clothing to AR glasses. Indeed, it’s been reported that Samsung will supply OLED displays for Google Glass.

The Future

While Samsung may be leading the pack when it comes to OLED innovation, the possibilities for the industry are astounding. A group of researchers at the Massachusetts Institute of Technology have developed a ruler with an embedded, transparent OLED display with pen stroke sensor that allows designers and illustrators to literally interact with their drawings. Dubbed “Glassified,” the device truly bridges the void between analog and digital. It can recognize patterns, measure angles, calculate areas, and even overlay hand drawn sketches with game-inspired animations.

"We have just started to explore some of the low-hanging fruit with our Glassified ruler project, but have many other use cases in the works," says Pattie Maes, director of the Fluid Interfaces research group at MIT.

The Fluid team has no interest in marketing Glassified, but one of the members has promised to post DIY instructions. All the same, Glassified illustrates a more functional approach to OLED innovation. So, what are some other concepts OLED technology might allow?

OLED inspires us to rethink the very concept of display devices.

Maes adds that transparent OLED displays could allow developers to augment paper, books, and other surfaces with dynamic data—for example, textbooks that spontaneously render animations, graphics, and annotations.

One might also imagine an e-ink tablet (like the Amazon Kindle) with a touch-based OLED “scroll” that can be pulled out like a roll curtain, thus turning a beach-friendly e-reader into an everyday tablet computer. Similarly, this “scrollability” feature might allow tablets to be rolled up into devices the size of a pen.

A malleable, paper-thin sheet of transparent OLED could be applied to a pair of eye glasses—or, eventually, contact lenses—providing a solution for nearsighted consumers interested in AR glasses. Transparent newspapers that refresh themselves at a moment’s notice, like the ones in Minority Report, could be possible with OLED technology. Dimmable OLED windows may allow drivers and homeowners to control how much light they let in to their vehicles and homes. And OLED light fixtures could provide a viable light source from a device as compact as a Post-it note.

An Audi concept for OLED brake lights

Clearly, the applications for OLED technology are diverse, and progress is heading in many promising directions, creating a web of possibilities. While the advances of LCD and plasma technology over cathode ray tubes were certainly groundbreaking, OLED inspires us to rethink the very concept of displays. Now it’s only a matter of time before OLED’s manufacturing costs come down enough for large-scale deployment.

Until then, do enjoy your flat, rectangular iPad; pretty soon it will go the way of the VHS tape.



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