New Technology in Television
Plasma Tv
Plasma and LCD HDTVs may soon be sharing shelf space at your local electronics store with a new flat panel technology called SED TV. Developed jointly by Canon and Toshiba; SED stands for Surface-conduction Electron-emitter Display.
Canon 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 spring 2006. At present, it looks as if Toshiba will start manufacturing HDTV panels in earnest in 2007 barring any production problems.
How it Works
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. Remember, a sub-pixel is just one of the three colors (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! It’s sort of like an electron Gatling gun with a barrel for every target positioned at point-blank range. An army of electron guns, if you will.
This may bode well for video purists who feel that CRTs offer the best picture quality, bar none. 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. This is expected to increase in the future, but still works out to about 116 ftL (foot Lamberts) or more than twice a regular TV. To put this in perspective, a movie theater shows a film at about 15 ftL.
Life Expectancy
It does look like SED TVs will last a good while as it has been reported 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. That can be a while. Maybe yours will even show up on the Antiques Roadshow in working condition in the far distant future. Time will tell but “accelerated” testing results should always be taken with a grain of salt as it only imitates wear and tear over time.
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 this writer for most display technologies other than CRT. Watching the all-pervasive low-key (dark) lighting in
