Focus on 2005: OLED displays

04 Jan 2005

Our pick of three hot technologies that are set to light up the year ahead - part 3.

The dream

An active-matrix full-color display, made from organic light-emitting materials, that challenges the dominance of LCDs.

Current status

Passive matrix OLED displays are now starting to find their first applications in clam-shell style mobile phones, car dashboards and music players, but the technology potentially could do much more. "The first products are not very exciting in many ways because they do not exploit the flexibility of the technology," Hermann Schenk of materials specialist Covion told Optics.org. "What we are now seeing is that the active matrix technology - a more advanced technology that uses thin film transistor backplanes - is beginning to enter the market."

One of the most important highlights of 2004, was Sony's announcement in September that it was starting volume manufacture of active-matrix OLED displays for use its handheld PDA (CLIE PEG-VZ90). "The real message sent by Sony to the market is that the manufacturing and design issues of active matrix technology for OLED can be overcome," said Schenk. "The near term future is really in applications where you want to display video information at distances of up to 1 m from the user's eyes."

However, in the long term, OLED technology may not be confined to the world of personal electronics. The latest demonstrations are now able to offer the image quality of a cathode ray tube display in a flat-screen format. Seiko Epson of Japan unveiled the world's first 40 inch color OLED TV at the 2004 Society for Information Display symposium in Seattle, US.

At the same event, Dutch electronics firm Philips exhibited a 13 inch OLED display which it says demonstrates the feasibility of scaling up to large displays. Both Philips and Epson produce their displays using an inkjet printing process that deposits the light emitting inks onto a pixellated backplane.

There is no doubt that OLED is a versatile technology and ultimately its ability to be printed on flexible substrates could result in smart clothes with integrated displays. "My dream is that we have light sources or displays in the market that could be manufactured economically in customized shapes and formats - you could order 10 pieces, 100 pieces or 100 000 pieces," said Schenk. "[Because] the manufacturing technology is a printing process, you only have to alter the software code to change the layout."

Future challenges

Despite a series of technology breakthroughs, factors such as operational lifetime and cost of manufacture remain a concern. "The basic inventions have been made and it is now about improving the silicon processing so that OLEDs are stable enough to deliver consistent quality," commented Schenk. "Materials need to improve to get real market penetration in terms of lifetime."

Timeline

Throughout the next couple of years, it is likely that the main applications for OLED technology will continue to be dominated by the personal electronics market. "The type of application is exemplified by Sony's PDA," said Schenk. "Big companies like Samsung SDI are scaling up to be ready for supplying to the market around the turn of the year 05/06."

Author
James Tyrrell is reporter on Optics.org and Opto & Laser Europe magazine.