PORTLAND, Ore. Printing high-definition organic LED (OLED) displays with ultrahigh-resolution inkjet printers will lower the cost and increase the color accuracy of flat-panel televisions, according to Seiko Epson Corp.
Tokyo-based Seiko Epson will reveal details of its fabrication process at the Society for Information Display (SID) International Symposium, Seminar and Exhibition, running May 31-June 5 in San Antonio, Texas.
According to Satoru Miyashita, general manager of Epson's OLED Development Center, Seiko Epson will show an ink-jet printed 14-inch OLED display that the company claims has the same resolution as, and better color accuracy than, today's 37-inch 1080p high-definition TVs.
"Large-screen OLED TVs are the future," Miyashita said.
The company has been working since 2004 to perfect its microelectromechanical system (MEMS)-based inkjet printing process, which uses piezoelectric actuators to deposit precisely measured dots of different sizes onto transparent substrates suitable for fabricating OLED displays.
The low-temperature fabrication process for printed OLEDs is lower in cost than the high-temperature semiconductor processing required for conventional LED displays. OLEDs also offer a wider color gamut, enabling them to render colors more accurately, as well as a wider field of view and increased contrast over conventional LED-based displays.
To date, however, OLED use has been restricted to smaller screens as manufacturers have sought reliable methods to deposit the necessary organic compounds with sufficient uniformity on large substrates. While some research efforts use vacuum thermal evaporation (VTE) to fabricate large-area OLEDs Seiko Epson has concentrated on refining its inkjet printing process.
VTE is a subtractive process that requires placement of a shadow on top of the substrate in order to pattern the organic compounds. The inkjet process, by contrast, deposits a thin film of liquid organic compounds one drop at a time. Since the inkjet process is additive, it requires less raw material than VTE does. It also requires fewer steps than VTE, increasing manufacturing throughput.
In trial production runs of the 14-inch OLED television to be demonstrated at the SID symposium, Seiko Epson claims to have fabricated color films with greater than 1 percent uniformity, which exceeds the requirements for mass producing OLED flat panels. The company claims its process is close to being ready for prime time.