CHANGING CONSENSUS IN LARGE FPDs

Throughout the world, from the beginning of video displays, researchers have aspired to make a large "picture-television-on-the-wall" flat-panel display. In the Japanese displays industry and others, this desire was heightened with the advent of high definition television (HDTV).

In Japan, with funding from Japan Key Technology Center (JKTC) and sponsorship from the Ministry of International Trade and Industry (MITI), a consortium of companies called "Giant Technology Corporation" (GTC) was organized in 1989 to make a one-meter AMLC FPD by 1994 (Elkus, 1991). This activity was highly publicized and highly politicized. The technical approach was to make a p-Si AMLCD using printing techniques instead of optical means for defining the circuits.

The GTC program has made significant progress in researching the printing technique. However, because of technical difficulties and significant budget cuts, it is no longer committed to making a one-meter panel as originally proposed.

Another project is being organized to make a large, one-meter HDTV plasma panel. This activity is expected to succeed where the AMLCD did not. The rationale is that plasma panels are already made by low-cost printing or screening techniques and that plasma phosphors are already developed, whereas the low- temperature p-Si process required for AMLCD is not.

It is anticipated that GTC will continue research on process technologies for the one-meter p-Si AMLCD with reduced expectations and that a renewed effort will continue, possibly with the formation of a new consortium like GTC, to develop a one-meter plasma panel for HDTV.

Another consortium, called HDTEC, sponsored by the Ministry of Post and Telecommunications (MPT) and founded by JKTC, is directed at developing a large-screen projector for HDTV using p-Si TFT AMLCD light valves. This consortium is making significant progress (Yokozawa, 1991).

Both direct-view and projection technologies are being developed for large-screen (over 40 inches in diagonal) consumer and industrial HDTV. The projection technologies using CRTs and LCD light valves are now available in limited production. The leading producer is Sharp, which uses a-Si TFT LCD light valves with peripheral row and column drivers attached via TAB polyimide carriers.

Neither during the Japan trip nor while examining the literature did we observe sufficient activity to indicate that a direct-view FPD will be available, in production, before the year 2000. It still appears that the market for large-screen televisions will be served by both front- and rear-projecting CRTs and LCDs, which will compete for market share. Within the LCD approach, a-Si TFT and p-Si TFT LCDs will compete for market share.


Published: June 1992; WTEC Hyper- Librarian