SED Surface-conduction Electron-emitter Display Technology
Technology Overview & Description
SED, or Surface-conduction Electron-emitter Displays are a new, emerging technology co-developed by Canon and Toshiba Corporation. The hope for this technology is a display which reproduces vivid color, deep blacks, fast response times and almost limitless contrast. In fact, if you take all of the claims made by the backers of SED you would think that there should be no reason to buy any other type of display. A long life filled with bitter disappointments and lengthy product-to-market times have increased my skepticism and lowered my tendency to act as a cheerleader until products start to hit the market. As far as the specs go, this is one hot technology.
An SED display is very similar to a CRT (and now we come full circle) in that it utilizes an electron emitter which activates phosphors on a screen. The electron emission element is made from an ultra-thin electron emission film that is just a few nanometers thick. Unlike a CRT, which has a single electron emitter that is steered, SEDs utilize a separate emitter for each color phosphor (3 per pixel, or 1 per sub-pixel) and therefore do not require an electron beam deflector (which also makes screen sizes of over 42" possible). Just for clarity that means a 1920 x 1080 panel has 6.2 million electron "guns". The emitter takes roughly 10V to fire and is accelerated by 10kV before it hits the phosphor lined glass panel. Sound like a lot of power? It's all relative as a typical SED display is expected to use about 2/3 the power of a typical plasma panel (and less than CRTs and LCD displays).
OK, here's the real interesting news. SED display electron emitters are supposed to be printable using inkjet printing technology from Canon while the matrix wiring can be created with a special screen printing method. The obvious result is the potential for extremely low production costs at high volumes once the technology is perfected.
Canon debuted an SED display prototype at the la Defense in Paris in October 2005. The specs referenced a < 1ms response time, 100,000:1 contrast ratio, brightness of 400 cd/m^2, and 180 degree viewing angle in all directions. Actual shipping models are expected to fist be released by Toshiba in 2007. Pricing is expected to be less than LCD and plasma for the same size - we'll see.
SED Display Advantages
- CRT-matching black levels
- Excellent color and contrast potential
- Relatively inexpensive production cost
- Wide viewing angle
SED Display Disadvantages
- Unknown (though optimistic) life expectancy
- Potential for screen burn-in
- Currently prototype only