At the International Display Research Conference (IDRC) being held at Kent State University’s Liquid Crystal Institute in Kent, Ohio this week, Universal Display Corporation (Ewing, NJ; www.universaldisplay.com) and Seiko Epson Corporation announced significant advances in combining Epson’s ink-jet printing technology with UDC’s phosphorescent OLED PHOLED technology.

Ken Werner
Senior Analyst and Editor
of HDTV Retailer and
Mobile Display Report

The companies demonstrated "P2OLED" materials that combine the high efficiency of UDCs PHOLED phosphorescent technology coupled with ink-jet printing potential (we presume the P2 nomenclature stands for phosphorescent-printable). " This is an important step toward the realization of cost-effective, large-area OLED displays," said a UDC statement. After working together for less than two years, UDC and Epson are reporting what they call "key achievements in the development of a P2OLED system based on solution-processable, small-molecule PHOLED materials. These results include significant lifetime and efficiency advances for red and green color emitters."

As reported in a joint paper given by Michael Lu, UDC’s Senior Scientist, the companies have achieved the following P2OLED results:

• A saturated red color with CIE coordinates of (0.66, 0.34), a luminous efficiency of 7 cd/A and more than 14,000 hours of operating lifetime (defined as time to 50% of initial luminance) from an initial luminance of 500 cd/m2.
• Another saturated red with CIE coordinates of (0.67, 0.33), 11 cd/A and 12,000 hours of operating lifetime from an initial luminance of 500 cd/m2.
• A green with CIE coordinates of (0.34, 0.62), 33 cd/A and over 8,000 hours of operating lifetime from an initial luminance of 1000 cd/m2.

Commercial products using Universal Display’s PHOLED technology and materials, which have up to four times higher efficiency than traditional OLED systems, are already being manufactured using conventional vacuum thermal evaporation (VTE) equipment.

The ability to print OLED materials has been under development for some time. Initially, it was thought that only polymer OLED materials, discovered at Cambridge University and developed by Cambridge Display Technology (CDT), would be compatible with ink-jet processing. Small-molecule OLED materials, discovered at Kodak some years earlier, had a significant developmental lead, but they could not be solution-processed. Now, UDC and Epson have bridged that gap. And in June, DuPont announced a solution-processed, but non-ink-jet printing approach that the company will not describe. The company has shown an OLED display prototype fabricated with the technology, however.

So, how far away are UDC and Epson from supplying sample displays to manufacturers of cell phones and other portable products? For that matter, how far away is Epson from having Gen 4 or higher ink-jet printers? I will ask those questions face to face at FPD International in Yokohama next month, and I’ll let you know if I get any answers.