SED technology works much like a traditional CRT except instead of one large electron gun firing at all the screen phosphors that light up to create the image you see, SED has thousands of tiny electron guns known as "emitters" for each phosphor sub-pixel. A sub-pixel is just one of the three colours (red, green, blue) that make up a pixel. So it takes three emitters to create one pixel on the screen and over 6 million SED emitters to produce a true high definition (HDTV) image. One prototype has even attained a contrast ratio of 100,000:1. Its brightness of 400cd/m2 is a tad on the low side for an LCD TV and nowhere close to a plasma screen output.
Canon first started development on this imaging technique back in the mid 1980s and joined up with Toshiba for the project in 1999. Both formed a dedicated company for the technology called SED Inc. in 2004.
Neither of these companies is a notable player in the flat screen arena, but they are looking to make a big splash with SED TV. Test production runs are already underway with limited product availability expected by late 2006 in the US and Japanese markets. At present, it looks as if Toshiba will start manufacturing HDTV panels in earnest in 2007 barring any production problems. Entry level models are set to be 50" inches with top end models set to go to 100" inches. The technology is cheaper to produce than LCD or Plasma with some analysts saying that 55" SED screens will eventually sell for $1,000 or less.
Research shows that SED TVs will last a long time. Tests reveal that that the electron emitters have been shown to only drop 10% after 60,000 hours, simulated by an "accelerated" test. This means that it is likely the unit will keep working as long as the phosphors continue to emit light.
SED TV Compared to CRT
SED is flat. A traditional CRT has one electron gun that scans side to side and from top to bottom by being deflected by an electromagnet or "yoke". This has meant that the gun has had to be set back far enough to target the complete screen area and, well, it starts to get ridiculously large and heavy around 36". CRTs are typically as wide as they are deep. They need to be built like this or else the screen would need to be curved too severely for viewing. Not so with SED, where you supposedly get all the advantages of a CRT display but need only a few inches of thickness to do it in. Screen size can be made as large as the manufacturer dares. Also, CRTs can have image challenges around the far edges of the picture tube, which is a non-issue for SED.
SED TV Compared to Plasma TV
Compared to plasma the future looks black indeed. As in someone wearing a black suit and you actually being able to tell it's a black suit with all those tricky, close to black, gray levels actually showing up. This has been a major source of distraction for most display technologies other than CRT.
Watching the all-pervasive low-key (dark) lighting in movies, it can be hard to tell what you're actually looking at without the shadow detail being viewable. Think Blade Runner or Alien. SED's black detail should be better, as plasma cells must be left partially on in order to reduce latency. This means they are actually dark gray – not black. Plasma has been getting better in this regard but still has a way to go to match a CRT. Hopefully, SED will solve this and it's likely to. Also, SED is expected to use only half the power that plasma does at a given screen size although this will vary depending on screen content.
SED TV Compared to LCD
