Toshiba has put back the debut of SED (Surface-conduction Electron-emitter Display) TVs. Most recently earmarked for a Q4 introduction, when the TVs will now appear is anyone's guess - Toshiba certainly isn't saying.

The Japanese giant blamed the delay on Canon, which is developing the SED panels due to be used in Toshiba's TVs. "The decision is based on information provided by Canon, indicating that Canon will not be able to provide SED panels to the original schedule," Toshiba said today.

For its part, Canon said it was delaying the panels to establish the technology it needs to mass-produce them more cheaply.

The promise of SED technology is the ability to produce a TV as thin as an LCD or plasma display but deliver the colour intensity and refresh speed of an old-style CRT screen. The technique essentially used an electron emitter for every pixel and places them all very close behind a phosphor-coated display panel. For each pixel, electrons are sent speeding toward the phosphor - on impact, they produce a flash of light, just like a CRT. By targeting the individual red, green and blue colours of each pixel, however, the displays can be scaled to support HD resolutions.

Or so the theory goes. Canon has been pioneering the technology since the mid-1980s, but 20 years on it has still to come to market. Toshiba partnered with Canon in 2004, and the two have continually failed to meet launch deadlines ever since.

To be fair, Toshiba's last pronouncement, in December 2006, on the matter timelined volume production for 2008, with a small number of sets appearing in late 2007 - a schedule revised from an October 2006 plan to introduce 55in sets in July this year. Earlier this year, Toshiba said it was selling its stake in the two companies' joint-venture to Canon.