die technologie der Zukunft heißt: OLED (Organic LEDs )!
daz1 : die technologie der Zukunft heißt: OLED (Organic LEDs )!
By David Lieberman
(11/11/99, 2:48 p.m. EDT)
SAN JOSE, Calif. ? Organic LEDs (OLEDs) appear to be reaching critical mass as a next-generation flat-panel display technology. An annual display-industry report released by Stanford Resources Inc. projects dramatic growth for OLEDs over the next few years, as several companies make strides in bringing the technology to the commercial market.
"Rapid developments in OLED technology are driving a high-growth forecast for this new display, from $3 million in 1999 to $717 million in 2005," according to Paul Semenza, director of market analysis at Stanford Resources.
Some of the major players behind OLEDs see in these light-emitting plastic displays the potential for low weight, profile, power and cost. Sources said the dollars and man-hours being poured into OLED development may help move these panels from lab to street in record time for a new display technology.
David Mentley, Stanford Resources vice president, ticked off "the set of features that's really attracting people to OLED." The technology is "emissive rather than reflective," he said, "has good color and thin form factor, it's very fast, has very low materials cost and, the way things are going, it will be low-power. The low-voltage aspect is important because it gets away from all those problems plaguing electroluminescent [displays], plasma display panels and other emissive displays."
Mentley pointed to an explosion in OLED R&D. "It's amazing that things have gone from a handful of projects to about 60 at different companies and universities within three years," he said. "And it's a pretty fast-growing list."
The OLED market is "just starting right now," Mentley said, and it will take time before the technology scales up in size and resolution to make major inroads. "The volume is starting off fairly slow and there will not be hundreds of millions of dollars of them sold in the next few years," he said.
Pioneer Electric Corp. is already producing OLEDs for car radios, and Philips and Sanyo are independently gearing up to produce small OLEDs. Mentley said Pioneer has begun transferring its OLEDs to an unidentified Japanese OEM making an in-car traffic management system.
The displays recently got a boost when IBM announced it had narrowed its list of research candidates for flexible displays to the OLED and electronic ink. Big Blue has cranked out a 6-inch OLED prototype.
A "key demo" for Tokyo-based Pioneer's OLED, which it calls an organic electroluminescent (EL) display, "is an in-dash unit placed directly under two strong halogen lamps," said a Pioneer spokesman. The OLED combines a green dot-matrix section on the left with a blue dot-matrix section on the right, and a red/yellow line of legends running across the bottom.
"Any normal display would have been totally washed out and unreadable, but [here], every bit of information can be read perfectly," said the spokesman. "And not just straight on, but at angles. This means that the vehicle's driver or passenger can view the entire readout from anywhere in the car, during daylight or [at] night," a fact that "rewrites the rules of mobile displays."
"I was very impressed with two new color OLEDs from Sanyo and Pioneer" on view at the recent Japan Electronics Show near Tokyo, said Chris Chinnock, senior editor at the monthly Microdisplay Report newsletter (Norwalk, Conn.). Both companies, he said, "are licensing the Kodak small-molecule technology."
Sanyo's prototype is a full-color, 2.4-inch, 852 x 222-pixel OLED with an active matrix (AM) of low-temperature polysilicon thin-film transistors. At some as-yet undetermined resolution level ? "somewhere between 64 and 100-some lines," Mentley estimated ? an OLED requires an active matrix. And that's been the target of the collaboration between Sanyo and Eastman Kodak announced early this year, with Kodak (Rochester, N.Y.) contributing its organic-materials know-how and Sanyo its active-matrix expertise.
The Sanyo demo "is intended to be a monitor for a camcorder and has >200:1 contrast," Mentley said. "It has good color and brightness and no apparent speed problems."
Yoshikazuu Hori, vice president of Kodak and president of Kodak Japan, said the company intends to offer the panel for digital still cameras and PDAs. "The panel could immediately fit into digital still cameras," he said. "We are looking for early volume production."
Sanyo also showed a passive OLED prototype, a 1.3-inch, multicolor device. This, said Hori, will be available in 2000, targeting cellular phone applications.
But according to Yukinori Kuwano, president of Sanyo Semiconductor Co., "Active-matrix technology is essential to qualify OLED panels as the next-generation information display." The prototype AM OLED has reached a quality usable for products, and Sanyo intends to begin volume production of full-color panels in 2001. "It will take about one year to elaborate and establish stable, high-yield volume production," Kuwano said.
The prototype AM OLED has a simple structure, consisting of one glass substrate with an EL layer 150-nm thick and a metal cover. The prototype is 1.8 mm thick ? "thinner than a quarter," said David Williams, general manager of display alliances at Kodak. In the future, he said, today's 1.1-mm glass substrate will be replaced with plastic.
Pioneer, meanwhile, demonstrated "a full-color, QVGA, 5.2-inch model," Chinnock said. "It's got 150 [nits of brightness], with 1.6 million colors in video and 256,000 colors in RGB mode, and it's 1.4 watts. It looks quite good and has a wide field of view, although some contouring of color was evident."
Despite the progress, the Stanford Resources report cautioned that "OLEDs must overcome technical challenges and become price competitive with established technologies before the commercial impact expands."
Semenza said some of the growth will be "in new applications, but much of it will be at the expense of existing technologies, such as vacuum fluorescent displays [VFDs] and [conventional] inorganic light-emitting diodes." LEDs will decline from today's $523 million market to $418 million in 2005, according to the Stanford report. VFDs will drop from $648 million today to $432 million over that span.
Stanford's projection for VFDs notes that the technology has been hurt by LCDs in recent years and predicts that "beginning in 2001, OLEDs will usurp market share from VFDs" across the board in audio, video and consumer applications. Conventional LEDs, too, will suffer from the onslaught of OLEDs. "OLEDs will compete on costs with VFDs, passive and active-matrix LCDs and LEDs by 2005," the report predicts.
Sanyo's Kuwano sees LCDs as the main competition for OLEDs, with the latter being about one-third thinner and half as power hungry. Mentley said that OLEDs offer "a real advantage for miniature displays" over LCDs. "You can just throw away all the stuff you need to build an LCD."
Chuck McLaughlin, principal at McLaughlin Consulting Group (Menlo Park, Calif.), however, is skeptical about OLEDs' ability to deliver on all the promises.
"OLEDs are interesting, but they may get trapped in a competitive box between passive and active LCDs," he said. "For low-power applications, they simply can't beat a passive LCD in power or price. Sure, they look a lot better than passive LCDs but so did [conventional, inorganic] LEDs before them. "
As for AM LCDs, he said, "OLEDs can't beat the power, color and video. OLEDs require AMs, but high-power ones. They bring a whole new challenge to TFT design, and to what end?"
For small color video applications such as cameras and camcorders, McLaughlin granted that "the backlit AM LCD is vulnerable due to high power, but watch out for reflective AM LCDs."
Beyond all the attractive features of the OLED is one other major advantage: "the tool box available," said Mentley. "Molecular engineering is ideally suited to what academics can do. There are infinite possibilities here, instead, for example, of having to stick with some particular phosphor material. Things will just keep going and going."
?Additional reporting by Yoshiko Hara
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