Japan's public broadcaster, NHK (Nippon Hoso Kyokai) will be showcasing its latest flexible OLED (organic light-emitting diode) display prototype at the Open House event at its R&D center in Tokyo, held 5/26 to 5/29.

NHK and Panasonic have been conducting research into flexible displays that are thin, light, and bendable for many years now. Such display screens will one day be the main parts of easy-to-carry handheld devices and huge-screen Super Hi-Vision receivers in the home. The companies have refined the process of fabricating organic light emitting diode (OLED) and organic TFT in flexible displays and reduced the number of defective pixels in the display panel.

By investigated materials, patterns, and processes used to form small electrodes, wiring highly accurately on a plastic substrate and reduced the number of defects in a display panel, the companies have developed a 5-inch, QVGA (320 x 240 pixels) flexible display prototype. The images are in color although the stronger green pixels give the picture an overall green hue.

The companies optimized the process of forming coated polymer insulating films used within organic TFTs, and this resulted in an increase in the uniformity and stability of the display's characteristics. A highly efficient organic OLED had been obtained by improving the emitting material.

Compared to a prototype that was displayed by NHK two years ago, the most recent one benefits from a more reliable manufacturing process.

In May 2010, Sony showed a 4.1-inch OLED screen that could be rolled up. The prototype had a resolution of 432 by 240 pixels and could be flexed to a greater degree than the NHK display, although it exhibited bad pixels. Sony's full color OLED display could be wrapped around a thin cylinder.

The researchers are pursuing the development of OLED technology because it can produce a picture that is brighter and more vibrant that an LCD (liquid crystal display) and doesn't require a power-hungry backlight.

NHK plans to continue developing new fabrication methods, such as printing techniques and materials for displays with larger screen and higher resolution.