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FED

(Field Emission Display) A flat panel display that provides an image quality equal to or better than a CRT. Like a CRT, it uses a vacuum-filled chamber and phosphor-coated glass. However, instead of illuminating phosphors with three "guns" that scan the entire screen, FEDs use hundreds of millions of stationary emitters, with some 1600 of them per pixel. Some designs use low voltage emission and high current while others use high voltage and low current, which is more like a standard CRT.

Invented in the 1970s
Although the field emission display was invented in the 1970s, it took more than two decades to produce working models. With hundreds of patents on the technology, PixTech was the pioneer in this field with small displays in production in the late 1990s and early 2000s. Other companies including Futaba, Ratheon, Motorola, TI, Candescent and Sony were also involved in FED development. However, during that same period, advances in active matrix LCDs were extraordinary, and although FEDs were considered more rugged and useful in harsher environments than LCD panels, the technology has yet to see any mass market. See surface-conduction electron-emitter display.




The FED Technology
This illustration, which is somewhat conceptual, shows how the energy flows from the microtips to the phosphors (anode). Electrons from the negatively charged (-) cone column are emitted when the gate row is positively charged (+). The electrons then flow to the phosphors that are momentarily given a larger positive charge (+++), which, in this diagram, are the red ones. The pixels are addressed 180 times per second, providing a very high refresh rate. (Redrawn from illustration courtesy of PixTech.)






surface-conduction electron-emitter display

A thin CRT technology developed by Canon that was based on field emission technology (FED). Announced in 2002, Canon created a joint venture with Toshiba to develop surface-conduction electron-emitter (SED) TVs, and prototypes at the 2006 CES show in Las Vegas demonstrated remarkable clarity. However, a lawsuit over sharing licensed technology relating to carbon nanotube emitters caused Canon to buy out Toshiba's stake in 2007. Due to improvements in LCD TV technology, Canon later turned its attention to OLED displays and liquidated its SED Inc. subsidiary in 2010.

Similar to Plasma Displays
Using millions of low voltage emitters (one for each pixel) on the cathode plate and regular CRT-like phosphors on the glass anode plate, the SED display used a third of the power of plasma displays. See FED and plasma display.



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