As I stood in the corner of a small, cluttered optics lab at MIT, the professor flipped a switch. The room filled with an electrical buzz, and suddenly a holographic video popped out at my face.
The 3-D image was of a human rib cage, and it rotated in midair. And the holographic rib cage rattled me.
It was my first experience with a Display Of The Future, and it set me on a mission. In the subsequent years, I've been hunting down display prototypes, talking with experts, and visiting labs. In short, I've been on a quest for the perfect display.
Now You See It
Even though holographic video blew me away when I first saw it, I quickly composed myself. It's simply not the sort of thing that will be commercially available any time soon.
I talked to Gregg Favalora, 3-D expert and founder of Actuality Systems, about the commercial viability of high-resolution 3-D video. His company broke resolution records with its display-a 100-million-voxel (3-D pixel) device that made images for radiologists and engineers hunting for oil reserves. The details of these 3-D images look eerily realistic, but Actuality had a heck of a time finding the right market for it.
In the end, the company only sold 30 systems at $200,000 each and it has now ceased engineering operations. And that MIT holographic video system I saw in a few years ago is still trapped in the lab. The lesson: no matter how extraordinary your technology, it's impractical for the people unless you can efficiently manufacture it in large numbers.
I See Practicality
At the opposite end of the price spectrum is LCD. It's cheap as dirt thanks to the billions of dollars of factories built over the past two decades. I wanted to get a look at the way LCDs are made and try to find clues for how a more interesting or useful display-like a reflective e-reader or an OLED screen-could scale up and become cheap.
So I took a trip down to Applied Materials in Santa Clara, California, a company that supplies 90 percent of the LCD industry with manufacturing equipment. What I saw was impressive: the newest fabs are built around sheets of glass—backplanes of LCDs—that are the size of a garage door. They're only as thick as six sheets of paper, and each one can yield eight large screen TVs.
The machines that deposit electronics on the glass are behemoths-taller than I can reach and with an area slightly larger than a garage door. In a fab, six of these machines are arrange circularly, and from above they look like a giant mechanized flower. The sheets of glass slide in like a floppy disk into a drive, and come out coated with thin film transistors.
The bigger the glass, the more displays can be pumped out of a factory, and the cheaper all sizes of LCD displays become. According to Sid Rosenblatt, the CFO of Universal Display Corporation, a big fab can make six 50-inch LCDs every three to four minutes. At that volume, how can anything else compete with LCD?
Well, instead of beating them, startup Pixel Qi decided to join them. The company's screens are all LCD—built on the same lines and with the same materials as any other liquid crystal display—but with an additional mode in which the power-hungry backlight is off, and the display reflects ambient light.
I've seen Pixel Qi's displays and visited with Mary Lou Jepsen, the startup's founder and the former CTO of the One Laptop Per Child project. Jepsen spends most of her time in Taipei, the capital of Displayland, but on a sunny day last fall, I caught her at her houseboat in Sausalito. It was the perfect time and place to try out an LCD that is most impressive in bright light.
In its reflective mode, the display is black and white, similar to a Kindle or Sony Reader except it's faster-capable of video, albeit in monochrome. The first batch of Pixel Qi screens is scheduled to come off the line this month. Jepsen says more designs that further reduce power consumption are on the way. In one, she explains that the screen, when not needing to refresh, should be able to shut down the central processing unit(and wake it up within milliseconds when it's in use).
As for a color reflective mode, Jepsen says it could be possible in a couple of years. The concept, which involves a particular arrangement of liquid crystals, is based on her PhD thesis, but it's admittedly a more complex design than the first Pixel Qi screens. Her first priority, she says, is making sure that Pixel Qi can ship its first products quickly and successfully.
Bright and Beautiful
While Pixel Qi might be making cheap displays that are easy on the eyes and energy efficient, they can't compare to the beauty and simplicity of OLED screens, in which each pixel emits its own light. The whites are whiter, the blacks are blacker, and the overall image is just gorgeous.
Even better, the manufacturing process is as simple as it gets. It's layer of organic material that can be printed between two layers of electrodes. This means that OLED displays have the potential to fold, roll, and be built over large areas.
Concepts I've seen: a paper-thin, flexible display slammed by a hammer without breaking, a display that's see-through when the power's off, and large area OLED coating that act as a window, a wall, or a display, depending on its mode.
In terms of touch, I'm keeping an eye on a new type of technology that's being integrated into the electronic foundation of OLED displays and LCDs too. It's called in-cell technology, and there are a number of variants, but one type incorporates photodetectors into the pixels of a screen. It's ideal for OLED displays, because it can be added without adding thickness, allowing them to maintain their sleek good looks.
If there were ever a perfect display, OLED is it.
In a conversation with Vladimir Bulovic, a professor at MIT (and star of the famous light-emitting pickle video) we waxed poetic on the possibilities of OLEDs. Bulovic believes that it's only a matter of time before OLEDs take their rightful place at the head of the display industry. The reason we have to wait is simply bad timing. "If back in the 1970s, we had OLEDs, no one would even know what an LCD is today," he said.
The widely understood problem with OLED displays, however, is that the technology doesn't exist to mass manufacture them on large sheets of glass like those I saw at Applied Material. Therefore, their beauty is relegated to smaller screens like cell phone displays, Sony's 11-inch (expensive) TV, and concept demos.
Engineers are working on the problem, of course. Bulovic told me about a former student of his, named Conor Madigan, who has an OLED-printing startup in Menlo Park called Kateeva. I got a hold of Madigan who said his company, which uses a hybrid approach to printing large-scale OLED display, is well funded (even in these difficult economic times) and the display industry is really starting to push large-scale OLED technology.
While it's true that big display makers are promising big OLED screens in the next couple of years, I'm not holding my breath. Even when the technology for printing large-scale OLED displays arrives, it will still take significant investments to scale up manufacturing. It's difficult for companies to justify investing too much money in OLED displays while LCD sales are still doing well and continue to get cheaper. Besides, these large-screen OLEDs will still be made on glass, just like LCD, which keeps things rigid, fragile, and heavy.
In order to have a light, flexible, rugged OLED display, it's obvious that display makers must go with plastic instead of glass. Plastic Logic, is promising the world's first plastic-backed screens with printed organic transistors, by early next year.
I've handled a proto-version of Que, Plastic Logic's e-reader, at the company's Mountain View headquarters and was impressed by the form factor. While it's still rigid, it's light as a thin stack of papers. And because it's made of plastic, it's robust. I felt like flinging it across the boardroom where I sat with the head of marketing and a public relations handler. I didn't.
Here's the bad news for Plastic Logic: it all comes back to scalability. At the recent Printed Electronics conference in San Jose, I had lunchtime conversations with people who just shake their head at Plastic Logic's challenges. A number of them expressed skepticism that the manufacturing process could scale.
Printed organic transistors currently can't compete in speed with amorphous silicon transistors used in LCDs and OLED displays. And the company's printing technology is done in a single fab in Dresden, which could make it difficult to produce the e-reader in large volume. In other words, it won't be cheap or widespread, at least in the near future.
Roll With It
However, the folks at HP Labs think they have a scalable way to make plastic-backed displays with fast silicon transistors. On a recent tour of HP Labs I saw the proof: sheets of plastic, tens of meters long, are rolled onto tubes and are loaded and locked into a system that imprints silicon transistors onto the material.
Carl Taussig, the director of HP's information surfaces lab, walked me through the process of the so-called Self Aligned Imprint Lithography. Plastic, with a shiny coating, spins on a series of cylinders, where it is exposed to chemicals, ultra-violet light, etching solutions, and ionized gasses. The roll-to-roll setups are compact, and they don't require clean-room level purity that other display processes do.
Taussig, who is also responsible for inventing the DVD-RW, showed me prototypes, built with HP's silicon-on-plastic transistors. One of these plastic backplanes controlled an E Ink display. Some of the pixels that were supposed to be black appeared gray, but these prototypes help the researchers find the problems in the roll-to-roll process. If they see a blown-out pixel, they retrace their steps to find where in the process the problem arose.
In another demonstration, I saw a new type of reflective display developed at HP that was about the size of a smart phone screen. It has color and video and is one of the best-looking reflective screen I've seen. Technical details were sparse (they will come out early next year), but Taussig told me that part of the trick is to make a pixel out of three layers of color dyes that take incoming white light and reflect specific colors of it back at you, something like the way that butterfly wings reflect light.
Within Two Years
While Taussig doesn't think roll-to-roll will replace LCD processes anytime soon, he hopes it can help plastic become the foundation for reflective displays as well as emissive displays like those made of OLEDs. HP has licensed its roll-to-roll technology to PowerFilm, a thin film solar manufacturer. And recently, PowerFilm's subsidiary Phicot has started to commercially developing the process for electronics. The first products will be displays for soldiers that may be integrated into clothing or wrap around their arms.
Combining HP's roll-to-roll manufacturing with OLEDs and a reflective reading technology is the closest thing to the perfect display that I've seen. So I ask Taussig how long it's going to take to make the process reliable. He's optimistic that Phicot can iron out the problems soon. "To be successful we need to roll this out within two years," he says, since the first plastic displays will hit the market in 2010.
In talking with Taussig, it's clear to me that even though he's a researcher, he's focused on making plastic displays practical. He knows the only way to do that is with solid, cost-effective manufacturing. Once the manufacturing problems are solved, he says, plastic displays become inevitable. "My grandkids will never believe that we made displays with glass," he says. "Everything will be on plastic."
I can't wait. The perfect screen will be lightweight, energy-efficient, and able to take various forms—flexible, transparent, and with touch or some other form of gesture recognition. I want colors so vibrant that images look real enough to grab. Still, I want to read on it without feeling like I'm staring at a flashlight. And it's got to be cheap.
So far, the displays I've seen come close. And while nothing yet gets it all right, there are some up-and-coming technologies-and, crucially, emerging manufacturing processes-that give me confidence that the perfect display is on the way.
Kate Greene spends most of her day staring at the screens of her MacBook Pro and iPhone. She became a journalist by way of physics, where she worked in a basement lab with lasers and a lot of liquid nitrogen. Currently, she writes for publications like The Economist and Technology Review and goes on display hunts for Gizmodo. She can be found on the Internet at kategreene.net and on twitter