In recent years, substantial research, manufacturing development and investment has been put towards Field Effect Devices (FEDs). Perhaps preeminent was the effort at Candescent Corp. More recently was the joint venture between Canon and Toshiba related to the development of SED TVs. The TVs looked great but the production problems were never fully solved. In addition, the economics of entering the TV business and having to compete with TFT-LCD and plasma TVs were major factors in canceling these initiatives.

Art Berman
Insight Media Consultant

So…everybody knows that FEDs are dead, right. Therefore, I was surprised to find two entire sessions at the just completed Society for Information Display conference held in Los Angeles dedicated to FED technology. I attended the sessions and learned that there is meaningful activity ongoing in this technological area.

On the other side of the coin, there were no FED displays exhibited on the show floor. Sony was a no show as was their affiliated, Field Emission Technologies, Inc.- a clear negative indicator for commercial potential.

FED display activity is heavily Asia centric and consists mostly of collaborations between industry and academia. In Japan, Field Emission Technologies, Inc., Noritake Co., Fuji Electric Systems Co. and Nagoya University are collaborating. In Taiwan, National Chao Tung University, Chunghwa Picture Tubes Co., Tsing Hua University and ITRI are working together. Others include DuPont, Samsung and the University of Illinois-Champaign.

The results being reported at the conference include both experimental and modeling work intended to increase the understanding of fundamental FED device physics and to address issues related to display production and performance. More specifically, some of the results reported relate to means of:

• Reducing blur in fast moving images
• Improving the electrical characteristics of the carbon nanotube emitters
• Self-focusing electron emissions so as to produce a smaller spot size increasing the resolution of the display

Other FED activities are focused on their use as a backlight. The roster of participants in this area includes: National Tsing Hua University, the Display Technology Center, Industrial Technology Research Institute, Dilight-Japan Co. and the Research Institute of Electronics, Shizuoka University. Once again, the research is based in Asia and is either academic or an academic - industrial collaboration.

In the backlight application, the case for FEDs does have merit. More specifically, a FED backlight might be less expensive than current approaches by eliminating the optical components that such systems require.

Some of the results reported at the conference relate to means of:

• Improving brightness uniformity
• Driving the FEDs so as to increase efficiency and reduce power consumption
• Means of producing the emitters with more desirable electrical characteristics

Clearly there is a good deal of meaningful R&D related to FED displays underway at creditable companies and universities. It is, however, somewhat hard to understand the rational, or at least the commercial rational. At this time, any improvements in FED image quality or manufacturability are unlikely to result in a high volume consumer product. One potential product that might be a legitimate target is that of specialty, high end monitors. Such monitors have exceedingly demanding requirements that could potentially be met by a FED and can command a unit price in the tens of thousands of dollars. None-the-less, this is a much smaller market.

The prospects of FEDs as a successful backlight would seem to be equally as uncertain. Although potentially as good as and maybe less expensive than current technologies, FEDs are trying to hit a moving target. That is, there is already a transition in backlight technology underway in laptops and TVs and it is towards LEDs and other alternatives (see Insight Media’s recent LCD Backlight Report). For FEDs to succeed, they will have to be better and less expensive than the next generation of backlight technologies, not current technologies.

However, as long as corporations and universities continue to invest in and work on FED technologies, Insight Media will continue to track developments and report back to readers.

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