Surface-conduction electron-emitter display

A surface-conduction electron-emitter display (SED) is a flat panel color television technology currently being developed by a number of companies. SED's use nanoscopic-scale electron emitters to energize colored phosphors and produce an image. In a general sense, an SED consists of a matrix of tiny cathode ray tubes, each "tube" forming a single sub-pixel on the screen, grouped in threes to form red-green-blue (RGB) pixels.
SEDs combine the advantages of CRTs, namely their high contrast levels, wide viewing angles and very fast response times, with the packaging advantages of LCD and other flat panel technologies. They also use much less power than an LCD system of the same size. To date, however, manufacturing and financial problems have prevented any SED system from entering commercial production.
SEDs are closely related to another developing display technology, the field emission display, or FED. The two differ primarily in the details of the electron emitters.
Description

A conventional cathode ray tube (CRT) is powered by an electron gun, essentially an open-ended vacuum tube. At one end of the gun electrons are produced by "boiling" them off a metal filament, which requires relatively high currents and consumes a large proportion of the CRT's power budget. The electrons are then accelerated and focused into a fast moving beam, flowing forward towards the screen. Electromagnets surrounding the gun end of the tube are used to steer the beam as it travels forward, allowing the beam to be scanned across the screen to produce a 2D display. When the fast moving electrons strike phosphor on the back of the screen, light is produced. Color images are produced by painting the screen with spots or stripes of three colored phosphors, one each for red, green and blue (RGB). When viewed from a distance, the spots, known as "sub-pixels", blend together in the eye to produce a single colored spot known as a pixel.
The SED replaces the single gun of a conventional CRT with a grid of nanoscopic emitters, one for each sub-pixel of the display. The surface conduction electron emitter apparatus consists of a thin slit across which electrons jump when powered with high-voltage gradients. Due to the nanoscopic size of the slits, the required field can be on the order of tens of volts. A few of the electrons, on the order of 3%, impact with slit material on the far side and are scattered out of the emitter surface. A second field, applied externally, accelerates these scattered electrons towards the screen. This field is on the order of kilovolts, but is a constant field and requires no switching, so the electronics that produce it are quite simple