Toshiba and Canon demonstrated a television with a 55in SED screen at the Ceatac exhibition in Chiba, Japan. They plan to put the screens into production next year.

At 55in, the prototype SED (surface-conduction electron-emitter display) screen is the largest ever demonstrated in public.

In development for 20 years, SED promises pictures that are as bright as CRT (cathode ray tube) televisions, while consuming one-third less power than equivalent-size plasma displays. And it shows none of the image delays often associated with flat-panel screens.

SED offers other advantages over existing flat-panel technology, Toshiba and Canon said. For example, the screens offer a wider viewing angle than other technologies and have contrast ratios of 100,000:1.

The companies will begin initial production of the 55in screens in July 2007, said Keiichiro Mori, chief specialist at Toshiba's SED Project Team, confirming that the production of SEDs, which had been delayed several times, is on track to begin next year.

The screens will go on sale first in Japan, Mori said. Pricing, as well as plans for selling SED televisions overseas, have yet to be finalised, he said.

At present, Toshiba and Canon plan to produce only 55in SED screens, Mori said.

Toshiba and Canon have delayed production of the screens several times, with engineers citing the difficulty of manufacturing the screens in volume. With the first screen to be manufactured next year, these difficulties appear to have been resolved.

The SED prototypes demonstrated at Ceatec were among the most popular products on display for visitors, who lined up to get a look at them. The demonstration, held in a darkened room, consisted of three 55in SED televisions used to show a variety of high-definition content, including a sumo wrestling contest, footage from a rock concert, and a clip from the movie Apollo 13.