Cost-effective Ink-jet Production of Large-area OLED Displays

The largest potential market for OLEDs is in wide area, low cost, flexible lighting, signage and displays. Here, the challenges include life, even distribution of voltage and the commissioning of low cost, high speed production, almost certainly by printing reel to reel. Seiko Epson Corporation, Japan reported on a joint paper with Universal Display Corporation, USA last week at the IDW Conference in Sapporo, Japan, significant progress in the development of P²OLED™ printable, phosphorescent OLED materials for use with solution-based manufacturing processes. Display manufacturers consider this a prospective solution for the cost-effective production of large-area OLED displays.

These advances are the result of a three-year joint development program during which the two companies focused on the successful demonstration of Universal Display’s P²OLEDs for application to Epson’s proprietary ink-jet printing process technology.

“It is a great honor to be working with the world-class team at Seiko Epson,” stated Steven V. Abramson, President and Chief Operating Officer of Universal Display. “Our joint development efforts to develop P²OLED materials and technology for use with Epson’s ink-jet printing technology have been highly productive. We have accelerated progress toward our commercial targets to enable the production of OLED displays that are low-cost, high-efficiency, thin, bright, and beautiful for a variety of consumer markets including large-area TV’s.”

“Everyone understands the potential of printable OLEDs, but we were forced to choose the others for commercialization up to now. The great achievement through our collaboration made the realization of printable OLED displays closer. Universal Display will continue to be the most advanced R&D company in phosphorescent OLED technology, and I appreciate them,” stated Mitsuro Atobe, General Administrative Manager, Display Development Division of Seiko Epson Corporation.

Given by Epson’s Takuya Sonoyama, the paper reported progress in red, green and blue P²OLED device performance in spin-coated devices and ink-jet printed devices. Demonstrating the high luminous efficiency of PHOLED technology, the team made significant progress in extending the operating lifetimes of its red and green material P²OLED systemsº Red with CIE(0.66, 0.33), luminous efficiency of 9 cd/A and greater than 50,000 hours of operating lifetime to 50% of initial luminance (at 500 cd/m²) and green with CIE(0.33, 0.63), 35 cd/A and greater than 50,000 hours (at 1000 cd/m²). The team also reported data for a new sky blue P²OLED with CIE(0.19, 0.40), 18 cd/A and greater than 3,000 hours (at 500 cd/m²). In addition, results with ink-jet printed P²OLED devices were reported which demonstrate the excellent film-forming ability of the small molecule layers. Ink-jet printed green P²OLED devices were also demonstrated to have the same efficiency as those of the spin-coated control P²OLEDs following an in-depth study of solvent selection and process optimization.

Universal Display’s PHOLED technology and materials, which offer up to four times higher energy efficiency than traditional OLED systems, are today being used in products manufactured using conventional vacuum thermal evaporation (VTE) equipment. P²OLED materials and technology, based on this same PHOLED technology, are designed for use with solution-based processes such as ink-jet printing.