Technical Feature

Inkjet Printing of Light-Emitting Polymer Displays

Tatsuya Shimoda, Katsuyuki Morii, Shunichi Seki and Hiroshi Kiguchi

Abstract

Based on the concept of a microliquid process, we have developed an organic electroluminescent display using conductive polymers, including light-emitting polymers. The technology of inkjet printing has progressed enough to be used for the microliquid process. First, we describe the process used to form a patterned thin film. This involves inkjet-related technologies, the self-patterning behavior of a microliquid on the substrate, and the drying process that defines the thickness profile and film properties. Some microliquid behaviors and related phenomena, along with properties of the resulting film, were identified as distinct from those coming from a macroscopic liquid, as a result of size effects. By fully utilizing these unique properties of microliquids, we have succeeded in fabricating color-pixel arrays by direct patterning of polymer solutions. As a result, an organic electroluminescent display with a vivid full-color image has been developed.

Keywords

• chemical synthesis;
• electrical properties;
• electro-optical materials;
• inkjet printing;
• liquids;
• polymers;
• solution processing

Tatsuya Shimoda, Guest Editor for this issue of the MRS Bulletin, is director of the Technology Platform Research Center at Seiko-Epson Corp. in Nagano, Japan, and a visiting professor at the Japan Advanced Institute of Science and Technology. Shimoda has been a member of the research staff at SeikoEpson since 1977. Until 1994, Shimoda was engaged in research and development work on magnetic materials and their applications; since then, he specialized in R&D work on thin-film devices and novel processes including a microliquid technology for inkjet printing of displays and semiconductor components.

Shimoda can be reached at Seiko-Epson Corp., 281 Fujimi, Fujimi-machi, Suwagun, Nagano-ken, 339-0293 Japan; tel. 81-266-62-8444, fax 81-266-62-8998, and e-mail shimoda.tatsuya@exc.epson.co.jp.

Katsuyuki Morii graduated from Osaka Prefecture University, Japan, in 1993 and received MS and PhD degrees in materials science from the Japan Advanced Institute of Science and Technology (JAIST) in 1995 and 1998, respectively. After working as an associate in the department of physical materials science at JAIST, he joined Seiko-Epson Corp. in Nagano in 1999, where he has been working on basic research concerning inkjet phenomena and conductive polymers. He is now a chief researcher in the Technology Platform Research Center.

Morii can be reached at Seiko-Epson Corp., 281 Fujimi, Fujimi-machi, Suwagun, Nagano-ken, 399-0293 Japan; tel. 81-266-62-8444, fax 81-266-62-8998, and e-mail katsuyuki.morii@exc.epson.co.jp.

Shunichi Seki received his BS and MS degrees in physics from the Science University of Tokyo in 1992 and 1994, respectively. In 1997, he joined Seiko-Epson Corp. in Nagano, Japan, where he has been working on the development of inkjet technology, especially its application to polymer light-emitting diodes in the OLED Product Development Department.

Seki can be reached at Seiko-Epson Corp., 281 Fujimi, Fujimi-machi, Suwagun, Nagano-ken, 399-0293 Japan; tel. 81-266-62-5607, fax 81-266-61-1545, and e-mail seki.shunichi@exc.epson.co.jp.

Hiroshi Kiguchi is a development manager at Seiko-Epson Corp. in Nagano, Japan. He joined Seiko-Epson in 1989 after receiving his BS degree in chemistry from Shizuoka University. He has been working on applied development using inkjet technology for industry on the IJ Industrial Applications Project since 2000. He is a member of the Chemical Society of Japan and the Society of Polymer Science, Japan.

Kiguchi can be reached at Seiko-Epson Corp., 1010 Fujimi, Fujimi-machi, Suwagun, Nagano-ken, 399-0295 Japan; tel. 81-266-62-6817, fax 81-266-62-6826, and e-mail kiguchi.hiroshi@exc.epson.co.jp.