LEDs eye benefits of going organic
By David Lieberman
EE Times
(04/10/01, 10:14 a.m. EST)
The organic light-emitting diode display is, by acclamation, going to be the next big thing in flat panels, but there's substantial disagreement on how fast this new display technology will get up to speed, where exactly it will find its ultimate application space and what other display technologies will suffer as a consequence.
One key claim to fame of the organic light-emitting diode (OLED) is its "beguilingly simple structure," according to Nick Colaneri, director of new technology at Uniax (Santa Barbara, Calif.), which was acquired by DuPont Displays Business last year. A backgrounder from Eastman Kodak Co. (Rochester, N.Y.) describes this structure as "a stack of thin organic layers-hole-injection layer, hole-transport layer, emissive layer and electron-transport layer-sandwiched between a transparent anode and a metallic cathode."
The flat-panel display (FPD) most often cited by OLED makers as their competition is the LCD, far and away the leading technology in the market. Advocates note that as an emissive display, the OLED needs no backlight and, thus, can be thinner and lighter than a liquid-crystal display, and has a wider viewing angle and temperature range and a speedier response to boot. Further, backers claim the OLED is more efficient than an LCD and thus extends the battery life of the end equipment.
OLEDs have an inherent cost advantage over LCDs as well, said Janet Mahon, vice president of technology commercialization at Universal Display Corp.
(Ewing, N.J.). "OLEDs have lower materials content, less capital-cost potential and fewer process steps than an LCD," she said: specifically, about 86 process steps vs about 200 for an LCD. UDC is focused on developing technology for flexible, plastic-substrate OLEDs.
Analysts are projecting great things for the OLED. Its "compelling features," said David Mentley, senior vice president at display watcher Stanford Resources Inc. (San Jose, Calif.), include "low voltage, good efficiency, possible high brightness, good lifetime, achievable full-color gamut and simple monolithic structure." Its demonstrated efficiency, Mentley said, "is changing almost weekly as new materials and structures are developed," even as its color gamut "is getting better on a regular basis" and its demonstrated lifetime "is improving fast."
Mentley termed the OLED "by far the hottest topic in the display industry. It's the most actively explored new display type, with more than 85 companies involved, and the total market is expected to increase from $18 million in 2000 to more than $714 million in 2005. Then it will explode between 2006 and 2010."
It's important to note, though, that $714 million will represent less than 2 percent of the overall FPD market, which Stanford estimates will hit $45 billion in 2005.
Though Mentley said the OLED "has one of the highest growth trajectories we've seen for a new technology in 20 years of forecasting," he cautioned that the forecast "assumes everything-packaging, materials, manufacturing, pricing and lifetime-is going to come together, and there are still many uncertainties."
There are currently two flavors of OLED: the so-called "small-molecule" OLED championed by Kodak; and the polymer-based OLED, pioneered by Cambridge Display Technology (Cambridge, U.K.) and known as LEP, for light-emitting polymer. "The key distinction is deposition process," said Colaneri of Uniax, with the small-molecule type using vapor deposition and the polymer type using solvent coating, a technology he called polymer's "enduring advantage."
Right now there are precious few OLEDs on the market, and all from Kodak licensees. These consist of displays from Pioneer Corp. (Long Beach, Calif.), which reside in one version of the Timeport cell phone from Motorola and in an automotive audio system from Pioneer itself; displays from TDK Corp. (Garden City, N.Y.), which have shown up in car audio systems from Alpine; and OLED-on-silicon microdisplays from eMagin Corp. (Hopewell Junction, N.Y.), which have been in selective sampling for a few months. General sampling is expected late this month.
Other announced Kodak licensees include Ritek Display Technology Corp., Lite Array, Sanyo Electric Co. and Nippon Seiki Co.
Announced licensees of Cambridge Display's technology include Delta, DuPont/Uniax, Hoechst/Covion, OSRAM, Philips and Seiko Epson, and CEO David Fyfe said that three of these vendors-Philips, Delta and OSRAM-are expected to announce products this year specifically for the cell phone market.
Some of the uncertainties over OLEDs are technical, due to the very early status of the technology, but sources said the nature of OLEDs is such that problems can be worked out fairly quickly. "OLED's prospects are dramatically great," said Darrel Hopper, display guru at the Air Force Research Laboratory at Wright-Patterson Air Force Base in Ohio, comparing OLEDs to the last "next big thing" in FEDs, field-emission displays, which have yet to have an impact.
"With OLEDs, you can produce various research types in a matter of hours," Hopper said, "whereas it might take days or weeks to try out new ideas in FEDs because they're vacuum devices and hard to pump out. Because of the different ways they're fabricated, OLED research can move very much faster."
"There are some remaining technical issues," admitted Les Polgar, president and general manager of Kodak Display Products, which was established in Walnut Creek, Calif., last October, "but we have demonstrated substantive proof of concept, causing quite a stir, and now it's a case of scaling up."
According to Dan Gisser, director of sales and marketing at Kodak, OLEDs have achieved the lifetimes necessary for small displays that get intermittent use, but they fall short for other applications. "We can now get 3,000 to 4,000 hours for full color, but progress is rapid and continual, so I'm confident we can readily get to 5,000 or 6,000 hours in a year," he said. "But it will be four or five years before we get to 10,000 or 20,000 hours of lifetime."
The Philips effort is "doing well," said Kenneth Walker of Philips Components (Sunnyvale, Calif.), "with a few hiccoughs here and there. We're working out industrialization, trying to build a consistent product at a consistent price." Walker admitted, however, that "we're going through some growing pains, and it's taking longer than we hoped."
Most of the uncertainty over the OLED is a matter of its immaturity. "As a future technology, it's as promising as anything I've seen," said Joel Pollack, vice president of the Display Products Business Unit of Sharp Electronics of the Americas (Camas, Wash.), "but it'll take awhile until it gets significant market share. It will be difficult for OLEDs to take a big share without the infrastructure in place. There's always a lag between viability and share."
OLED makers are "demoing really cool stuff that's almost paper thin," said Tom Martin, worldwide program director for flat panels at IBM Corp. (Research Triangle Park, N.C.), "but they're still in the early development cycle. Once the development hurdles are overcome and yields prove reasonable, then they'll have the manufacturing hurdles of how do they make them for X cents per square inch to be competitive."
Added Bruce Berkoff, executive vice president of marketing at LG Philips LCD Co. Ltd. (Seoul, South Korea): "OLEDs will be there in five years but it'll be 10 years before they have the infrastructure to get their cost down."
The OLED developers have big plans for their technology, perceiving markets in backlights and simple alphanumeric displays all the way up to very large displays for HDTV and very high-resolution microdisplays for wearable monitors.
According to analyst Mentley, there are currently "over 20 OLED fabs under construction or in planning." Yet, he said, "Uncertainty abounds in the technology, the markets and business models for making money. All successful display technologies have developed in concert with appropriate applications: the TV and monitor for the CRT and the watch, pocket TV and notebook computer for the LCD. A compelling application is needed to drive a new technology forward." But the application that will be "uniquely served by the [OLED] technology" has not yet appeared, Mentley said.
Gisser said Kodak's initial focus will be on 1.5-inch to 5- or 6-inch displays, with probable product candidates being "digital cameras, camcorders, high-end 3G phones and PDAs." The company hopes "to be able to show something in the 10-inch range" this year, he added.
The target of much of the early OLED activity is the cell phone. Paul Semenza, manager of strategic-market analysis at Stanford Resources, noted a movement in cell phone displays from monochrome passive LCDs to color passive LCDs and said he expects an eventual shift to color active-matrix LCDs. Nevertheless, he noted, "This could get disrupted if OLEDs start shipping in volume for mobile applications, particularly in simple alphanumeric displays, which are huge volumes and low average prices. But there's little history for OLEDs and vendors will want to see return on investment. Prices are still in the early-adopterish phase at this point."
Stanford's forecast for cell phone displays through 2006 indicates "a large share for OLEDs," said Mentley. "There are probably a half dozen companies targeting the same market segment with OLEDs and are poised to do quite a strong battle here."
As for full graphics OLEDs, these will start to have an impact in 2003, Mentley said, for such applications as camcorder viewfinders and navigation displays. And as the technology scales up in size, "OLEDs will affect notebook computer and desktop monitors after 2004," he predicted.
The bulk of the OLED market will initially lie in simple displays, according to Stanford's projections, with a gradual growth in size and complexity. "The best opportunity for OLEDs is in small displays," said Philips' Walker. Initially, he said, the company hopes to "get wins in cell phones or smart handheld devices and use that to drive up some volume and then go to larger screen sizes."
The "saving grace of OLEDs," according to Stewart Hough, vice president for business development at Cambridge Display, is that they "can go into such simple products as cell phones." As a result, "If we can satisfy that market, then we have an economic base to make investments" to scale up to larger screens.
The low-end market for character and segmented displays is traditionally served by vacuum-fluorescent displays (VFDs) and inorganic LEDs, and it will be these applications that "provide the first target markets for OLEDs," said Semenza at Stanford Resources. "They could rapidly be pushed into a marginal position by OLEDs."
The VFDs in particular, which enjoy about a $700 million market in cars, appliances, VCRs, business equipment and instruments, are "up against a wall," said Mentley. "They're not getting much better and can't get much cheaper."
But don't count VFDs out yet, said Albert Smith, executive vice president at VFD specialist Noritake Co. Inc. (Arlington Heights, Ill.). "As with the anticipated introduction of FED [field-emission display] technology a few years ago, we believe that the industry needs to study OLED very carefully before reaching conclusions about its potential to replace or supplant any VFD applications."
The VFD, Smith said, "is the most robust display product available, with special features that have been proven to work in real-world, time-tested applications and in the most severe of environments. The challenge for OLED will be to meet the challenges our products successfully meet everyday, including durability, readability in both the dark and in sunlight, and availability.
"VFD customer quantity demands may range from as few as 100 to over 100,000 pieces per month," said Smith. "VFD tooling and setup costs are low and very flexible, allowing for the shipment of low minimums, which is important in the engineering of expensive or custom products designed to be manufactured in small quantities."
Certain LCD makers have also been fielding displays that have the look of an emissive display like an OLED or VFD. The so-called "LCID" technology of Three-Five Systems Inc. (Tempe, Ariz.), for example, has been successfully fielded in character formats as a VFD/LED replacement.
"It gives the same look as an OLED but it's much cheaper and lower power," said Rob Harrison, vice president of the company's passive-LCD group.
Optrex America Inc. (Plymouth, Mich.) has a similar automotive LCD entry called MTN, for modulated twisted nematic, which John Cramer, marketing and business development manager, said "looks like OLED."
As for OLED-on-silicon microdisplays, eMagin president Gary Jones cited customer interest "in consumer videogames, both arcade type and PC based; high-end cameras and camcorders; ultraportable wearable computers; and, longer term, in handheld applications such as Web-based cell phones."
All in all, "This technology is still in version 0.9," said Stanford's Mentley. "There are bound to be many issues that pop up during the rollout stage. It happened with plasma, it happened with TFEL [thin-film electroluminescent] and even with LCD. New display technologies take years to perfect after they enter the market. This also points out the folly of predicting multibillion-dollar market growth within a few years."
The bottom line, he said, is that "the OLED must be price and performance competitive before there's a commercial impact. People who pay $5 for an LCD won't pay $25 for an OLED because it's new. They'll pay $5."
COMPANY CONTACTS
Cambridge Display Technology
(559) 645-1034
www.cdtltd.co.uk
EETInfo No. 625
eMagin Corp.
(845) 892-1900
www.emagincorp.com
EETInfo No. 626
Eastman Kodak Co.
(716) 724-4000
www.kodak.com/go/oel
EETInfo No. 627
Philips Components
(408) 617-7700
www.philips.com
EETInfo No. 628
Pioneer New Media Technologies Inc.
(310) 952-2111
www.pioneerusa.com
EETInfo No. 629
TDK USA Corp.
(516) 535-2600
www.tdk.com
EETInfo No. 630
Uniax
(805) 562-9293
www.uniax.com
EETInfo No. 631
Universal Display Corp.
(609) 671-0980
www.universaldisplay.com
EETInfo No. 632 |
