OLED Update: printheads, design contest, and improved materials

Epson OLED print head Seiko Epson Corporation has successfully developed the world's first print head using an OLED (organic light-emitting diode) light source. At present, almost all OLEDs are used in small display applications. Electro-photographic printing technologies for copiers and printers use either laser or LED light sources. Epson says that OLED technology will play a vital role in fulfilling the need for color printers that are smaller, have higher resolution, and faster printing speeds.

To achieve this demonstration, Epson partnered with Sumitomo Chemical Co. Ltd. to jointly develop a super bright OLED that can be used in printing.

During manufacturing, OLED material is applied directly onto a glass substrate, making it possible for a single substrate to have a linear light source. This enables the exact amount of light to be used to irradiate a spot with extreme accuracy to form highly uniform images, and for print heads to be made very small and ultra thin.

Tests using a prototype OLED-based print head have produced print-out quality comparable to or better than those produced by conventional laser printers.

Going forward, Epson says it will be possible to merge OLED technology with its low-temperature polysilicon TFT technology to achieve both higher printing resolutions and cost reductions by incorporating an IC into the print head.

OLED design contest launched

A design contest has been launched to stimulate ideas for the use of OLED technology in lighting applications.

Further details and entry forms are available at the OLED Design Contest website. Participants must enroll by May 31, 2006.

The contest, open to all but mainly targeted towards architecture and design students and professionals, is intended to highlight originality and versatility of OLED technology, by taking advantage of the novel characteristics that differentiate OLEDs from other illumination technologies currently present on the market. Entries should demonstrate the statement "With OLED, you can do it."

CDT reports progress in polymer lifetime development

Cambridge Display Technology has reported via Sumation, its joint venture partnership with Sumitomo Chemical, the further development of long lifetime, high efficiency light emitting polymers for full color, video capable P-OLED displays.

CDT has achieved blue fluorescent devices (CIE x = 0.14, y = 0.21) with 12,500 hours lifetime(1) from an initial luminance of 400 cd/m², and an efficiency of 9 cd/A.

Also announced are solution-processable red phosphorescent devices (CIE x = 0.67, y = 0.32) with 50,000 hours lifetime and an efficiency of 11 cd/A.

Green material with color co-ordinates of x = 0.36, y = 0.60 has also been developed; this represents a more saturated color than previously available from this class of material. Materials with strong colors are important in the design of full color displays with good efficiency and lifetime characteristics. Lifetime achieved for this material is 50,000 hours with an efficiency of 16cd/A.

The increased performance demonstrated by these latest data has prompted a switch to reporting lifetimes extrapolated from the higher luminance of 400 cd/m². Previously, numbers were reported from 100 cd/m². The blue, red and green materials reported here would have lifetimes of 200,000 hours, 800,000 hours and 600,000 hours, respectively, from an initial luminance of 100 cd/m².

Comments CDT's CEO Dr David Fyfe: "We are delighted to see rapid progress being made by the team from Sumation(TM), our joint venture operation formed in 2005. We place a very high priority on continuing to improve the underlying capability of P-OLED technology and the range of applications it can satisfy. We expect to continue to report further progress going forward. These data demonstrate the very significant synergy achieved with the combination of two very experienced teams in Cambridge and Tokyo."