FED (field emission display) technology is another emerging display technology that's challenging LCDs. However, FEDs must demonstrate clear advantages over LCDs if they hope to gain wide market acceptance. Some developers believe the low power, wide viewing angles, and good image quality of FEDs will make them an attractive alternative. But others think the relentless advancement of LCDs may be too much to overcome.
An FED is essentially a flat CRT. But instead of using a single electron gun to scan a phosphor-coated screen, an FED has a grid of individually addressable electron emitters on a flat substrate. A second transparent substrate contains colored phosphors. Each emitter pixel is addressed with electrical signals that trigger the emi
ssion of electrons, which react with the phosphor screen to generate colored light. The ultimate goal is to produce a CRT-quality image in a flat package that consumes little power.
Several varieties of FEDs are now under development by different companies (
see the list
). The most popular approach is to fabricate thousands or millions of tiny cone-shaped structures that emit electrons when voltage is applied. Some FEDs add voltage grids that help focus the electrons and increase voltage levels. Developing the materials, architectures, and manufacturing expertise to fabricate these electron emitters is one of the major challenges facing FED developers.
The advantage of using higher voltages is that it will let FEDs work with existing CRT phosphors. Lower-voltage approaches rely on the development of new phosphors that can operate efficiently and with long lifetimes at reduced voltage levels. There have been several recent advances in this area.
The discovery a few years a
go that certain types of diamond films are excellent electron emitters is also helping to fuel FED development. Researchers are looking for ways to improve the quality of these films and make them easier to manufacture.
Several companies are expected to demonstrate prototype FEDs this year, but that doesn't mean mass production is imminent. As IBM's Steve Depp points out, "From our experience in the AMLCD [active-matrix LCD] area, once good prototypes are demonstrated, it's about 2 1/2 years before they show up as actual products in quantity. It takes time to build a factory and establish other aspects of the infrastructure. Consequently, I think we're talking about mid-1997 before we see FEDs in any reasonable volume."
Canon
Tokyo, Japan, and Lake Success, NY
Coloray
Fremont, CA
FED Corp.
Hopewell Junction, NY
Futaba
Chiba City, Japan, and Plymouth, MI
Micron Display Technologies
Boise, ID
Pixel International
Rousset, France
Raytheon
Quincy, MA
SI Diamond Technology
Houston, TX
Silicon Video
Cupertino, CA
Texas Instruments
Dallas, TX
FEDs: Wait A Few Years
