MAJOR TECHNICAL FINDINGS

As a result of its study the committee observed several major areas that show the direction and extent of the maturity of FPDs in Japan:

During the 1970s and 1980s, all of the flat-panel technologies were developing on a relatively broad front in the United States, Europe, and Japan. However, because of cross-coupling (Tannas, 1985), LCD technology could not be applied to large arrays such as are required for television and computers. The contrast and viewing angle were degraded by a so-called sneak circuit between picture elements (pixels) turned on and those intended to be left off. This effect can be minimized with AMLCDs, in which diodes, field-effect transistors, or other nonlinear elements are constructed at each pixel. In the United States, the cost of such an LC FPD has been considered prohibitive; but several Japanese companies have perfected techniques to mass-produce AMLCDs for HIC displays, to add color, and to improve viewing angle performance.

In parallel to the active matrix approach, a concerted effort was applied to passive matrix LCDs. A series of developments has rendered the super-birefringent form of LCD manufacturable with wide viewing angle and in black and white monochrome, as well as color. This form of LCD, called compensated supertwist, possesses sufficient nonlinearity for manufacturing of HIC computer displays. As yet, it does not possess sufficient speed or color for television video.

In the United States, by comparison, there has been limited research and development on AMLCDs and supertwisted nematic (STN) LCDs. At present, there are activities at Sarnoff Research Laboratory, Xerox PARC, and OIS Optical Imaging Systems on AMLCDs and at Standish and Tektronix on STN LCDs.

The development of successful techniques to matrix-address large arrays of LCDs during the 1980s is bearing fruit in the 1990s. The successful production of colored AMLCDs and low-cost STN LCDs in Japan has changed the entire picture in the FPD industry. It appears that, out of all the FPD technologies, the LCD will dominate through the 1990s; it also appears that the other FPD technologies, such as EL, plasma, light-emitting diodes, and so forth, will be relegated to custom markets.


Published: June 1992; JTEC_WTEC Hyper-Librarian