South Korea's Samsung Electronics has developed a prototype OLED (organic light-emitting diode) display that it says is the largest yet made by any manufacturer.

OLEDs have been viewed as a potential replacement for LCDs (liquid crystal displays) and PDPs (plasma display panels) in some applications for several years. OLEDs don't need a backlight and so power consumption is lower than LCDs and OLEDs are more responsive to fast-moving images, according to the technology's backers. This has made them attractive to portable electronics product makers and flat-panel TV producers.

However, development of the technology has not yet reached the point where mass commercialization is possible. The only exception to this is a few small screens being produced for mobile phones, digital cameras and PDAs.

The Samsung screen is 21 inches in size and offers a WUXGA (Wide Ultra Extended Graphics Array) resolution. Other specifications include a brightness of 400 candela per square metre (nits) and a contrast ratio of 5000:1, which makes it suitable for viewing high-definition video, according to Samsung.

The screen's production process uses Amorphous Silicon (a-Si) technology, which is also used in some LCD production, and so the screens can potentially be mass produced on Samsung's existing LCD manufacturing lines, the company said.

At present commercialization is under consideration, said Chae Su Yeon, a spokeswoman for Samsung in Seoul.

In 2004, Japan's Seiko Epson displayed a prototype OLED screen measuring 40-inches across. Samsung said its latest prototype beats that in terms of size because the Seiko Epson panel wasn't a single panel but constructed from four 20-inch panels placed together.