SID 2000: OLEDs steal the show at Society for Information Display annual meeting
Editor's Report
Image is everything, so the line goes. The saying was never truer than at last week's Society for Information Display Annual Meeting (SID 2000; May 15-19; Long Beach, CA). Targeted at display researchers, manufacturers, and OEM customers, the show attracted 6600 attendees and 240 exhibitors.
The show was not all about display panels themselves. Booths like <%=company%> (Rochester, NY), showcasing full color organic light-emitting diode (OLED) displays operating at video rates may have attracted crowds (see Figure 1), but unglamorous yet necessary elements such as power inverters, optical and electrical connectors, backlighting, and test equipment figured heavily in the exhibitor mix.
The flat panel display market is poised for a growth surge in the next five years, slated to rise from the 1999 figure of $19.7 billion to $44.9 billion 2005 according to market analysts. The market drivers at that point will be cell phone handsets, PCs, notebooks, and other personal display devices. Based on cell phone unit projections, the annual demand for handset displays alone will rise from the current value of 378 million units in 2000 to reach 787 million units in 2006. As a side note, Motorola (Copenhagen, Denmark) plans to release a handset featuring an OLED display in June, opening up the commercial market for that technology.
One of the most interesting aspects of this growth phase is taking place in the liquid crystal display (LCD) market as supplier dominance gradually shifts from Japan to Korea, with companies like Samsung and LG Phillips stepping to the forefront. "It implies a sea change in where displays are made," said Kenneth Werner of Nutmeg Consultants (Norwalk, CT). "The Japanese hegemony is over."
OLED displays heat up
Unsurprisingly, anything to do with OLED displays drew a crowd (see DappConn '00: OLEDs Move Into the Spotlight). Neil Greenham's seminar on OLED display was standing room only, as the University of Cambridge (Cambridge, UK) lecturer reviewed the state of the art. Although full color displays have been produced using so-called small molecule OLEDs, researchers working with polymer (large molecule) displays have had difficulty developing a true blue polymer. According to Greenham, Cambridge Display Technology Ltd. (Cambridge, UK) has tackled this problem, developing a blue polymer that agrees well with the CRT blue. The company has made rapid progress using polyfluorines without vinylene bonds.
On the show floor, Kodak made a splash with a 5.5 in. digital OLED display that ran crisp, full-color video. The 1.8-mm-thick device features a 320 x RGB x 240 ((i.e. a trio of pixels at each of 284 x 220 locations) is driven by low temperature polysilicon thin film transistors (TFTs) fabricated on a glass substrate.
According to David Williams, general manager of Kodak's OLED Display Technology group, the company expects to demonstrate a 10 to 11 in. prototype in early 2001. "The challenge is in maintaining yield," he said, noting that in terms of performance, efficiency increases as display size grows.
Williams said that the company's smaller OLED displays will begin appearing in Kodak and Sanyo digital cameras and camcorders in the next year. "We're looking at product plans for cell phones," he added. The booth also featured full color 2.4 in. displays with resolution of 284 x RGB x 220 pixels (i.e. a trio of pixels at each of 284 x 220 locations) and a 0.17 mm pixel pitch. Like their larger counterpart, the displays ran video and offered a response time of less than 1 µs.
Polymer OLED
As holder of key intellectual property for small molecule OLEDs, Kodak is committed to going to market first with small molecule devices. Other market contenders such as Philips Flat Display (San Jose, CA) are working with polymer technology, instead. At SID 2000, the company demonstrated a 1.4 in. polymer LED display. Unlike small molecule OLED materials, which must be applied by vacuum sublimation techniques, polymer OLED materials are liquids that can be applied to a substrate using techniques such as spin-casting. In the case of the Philips device, an ink jet printer applied the pixels for the display.
Designed for cell phone video applications, the 96 x 64 pixel display offers 1.5 µs response times. "Our real focus is the telecom market," said Philips Components innovation manager Robert Jan Visser. The display generates 5 lm/W of output and operates on 6.5 V. The company projects release as a full product by November of this year.
Philips also showed a prototype two-color display, based on red and green pixels. "One of the issues still is to get long lifetime blue polymer," Visser noted.
Microdisplays on parade
At the eMagin Corp. (Hopewell Junction, NY) booth, meanwhile, the company's 0.78-in diagonal OLED microdisplay captured attention. Although the SXGA resolution (1280 x 1024 pixels) device operated in monochrome at the show, it is capable of running full color, according to president and CEO Gary Jones. "We take each group of four pixels and turn it into an RGBX unit. With filters on top and the right interface board it will do full color," he said. "The interface board didn't arrive." Ah, life in tradeshow land.
Using the same chip, the company did demonstrate a VGA resolution color quad (RGBX—the fourth pixel can be white, red, blue, or green) device capable of achieving 16 million hues. Although microdisplay manufacturers like Three-Five Systems Inc. (Tempe, AZ) have been building liquid crystal on silicon displays for some time, the eMagin device is believed to be the first commercial demonstration of an OLED fabricated on a silicon substrate. Applications for the technology include night vision and medical systems.
The company is currently working on an SVGA color triad (RGB) device designed for consumer products such as DVD players and PCs. The devices would be implemented as head-mounted displays, and will require minimal interface to the host unit.
Compare and contrast
Perhaps the most entertaining aspect of the show was the Display Technology Showcase, a large, dimmed tent on the show floor in which offerings from various manufacturers were segregated by type (microdisplay, desktop flat panel display, high definition television (HDTV displays, etc.) and lined up side by side. More important, they all played the same test pattern or video sequence, so that for once the observer could really compare performance.
The microdisplay category was fascinating. The last time I tried on a head up display, at Aerosense 1999, the heavy, bulky unit hurt the bridge of my nose and made my head feel unbalanced. The microdisplays shown at SID weighed mere ounces and were mounted on ordinary glasses frames.
In particular, I found the entry from MicroOptical Corp. (Westwood, MA) to be noteworthy. The image originated in an imaging engine located at the temple, and reflected off of a mirror perhaps 8 mm x 8 mm to reach the eye. The effect was uncanny—the full color image appeared to float over the background, and was visible even when I stepped outside of the tent and into the lights.
The technology has advanced significantly and is poised to move into the commercial marketplace. When the wireless industry rolls out the long-anticipated third generation (3G) technology, which will provide the bandwidth to support genuine wireless Internet, microdisplay manufacturers will be right there with feather light headsets that display entire web pages with apparent diagonals of 12 in. or more.
Plasma
For me, though, the most impressive contender in the Showcase wasn't a microdisplay but a macro display. And what a macro display. Plasmaco Inc. (Highland, NY) brought a prototype 60 in. plasma display with HDTV capabilities that was, frankly, eye popping. The 1366 x 768 pixel array generated 550 cd/m2 of 24-bit color, with a viewing angle of 160°.
Not being much of a gadget monger myself, I've never gotten too excited about HDTV, considering the resolution issue interesting from an engineering point of view but largely dismissable from a consumer point of view. Having seen the giant high-resolution picture side by side with a large conventional image, I am a convert. The picture was so crisp, I could almost believe I was looking at a live scene. In comparison, the conventional large screen set next to it appeared blurred.
According to Tom Butts, managing editor of VerticalNet's Digital Broadcasting site, full implementation of HDTV is still several years away. When it arrives, though, I'm going to march right out and buy myself a set. I'm going to start saving today. With a price tag of $30,000 and a power consumption of 750 W, I'll need to.
Look for more SID coverage over the next week, including an FED update and reviews of technical presentations.
By: Kristin Lewotsky, Photonics Online