Technology watch, SED – Surface-Conduction Electron-Emitter Display

May 19, 2005

SED DisplayTaking a look at the current crop of display technologies, one reality is hard to escape; we haven’t drastically improved on the nearly antique Cathode Ray Tube (CRT) televisions of years past. Sure we now have flat panels that can display resolutions of up to 1920×1080 pixels or higher in rare instances, but the often shunned CRT technology is capable of resolutions of 2560×1920 and higher, well within the future-proof 1080p spec.

Ok so flat panels don’t beat CRT’s on resolution, and to be honest they don’t really look better, with comparable resolutions. In addition both Plasma and LCD displays often fall short of CRT black levels, so why all the fuss? The flat screen of course, specifically screens less than 3 inches in depth.

What if a new display technology could combine the best attributes of both CRT’s and flat panel displays? Well I haven’t written this far to say wouldn’t that be nice, enter SED (Surface-Conduction Electron-Emitter Display). Spearheaded by Canon and Toshiba back in the mid eighties, SED appears to offer an excellent balance between cost, resolution and screen depth.

The inner workings of SED borrow from both LCD and Plasma technologies; a glass plate is embedded with electron emitters, one for each pixel on the display. The emitters on this plate face a fluorescent coating on a second plate. Between the two plates is a vacuum, and an ultra-fine particle film that forms a slit several nanometers wide. By applying voltage to this slit, the sets can produce a tunneling effect that generates electron emission. The panel emits light as the voltage accelerates some of the electrons toward the fluorescent coating.

SED displays offer brightness, color performance, and viewing angles on par with CRTs. However, they do not require a deflection system for the electron beam. Engineers as a result can create a display that is just a few inches thick; while still light enough for wall-hanging designs. The manufacturer can enlarge the panel merely by increasing the number of electron emitters relative to the necessary number of pixels. Canon and Toshiba believe their SED’s will be cost-competitive with other flat panel displays.

Canon and Toshiba hope to begin commercial production of SEDs for large-screen displays this year; possibly as early as August.



Posted by Bryan Greenway | | Filed Under Display Technology


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