SUBJECT AREAS

The site team identified six areas of flat-panel display technology for study. One person on the team was responsible for coverage of each area and the corresponding chapter in the report.

Liquid Crystal Display Materials and Related Technologies

The WTEC panel's objective in nonemissive displays was to find innovations in liquid crystal materials, both of the low- molecular weight and polymeric varieties. Panelists were aware of several synthesis groups in Belarus, Russia, Ukraine, and other FSU countries. The panel wanted knowledge of what these groups were making in terms of new materials. Panelists knew of some innovations in photoaligned polymers emerging from the Moscow and Kyyiv regions. The use of these photoaligned polymers in such things as alignment layers, retardation layers, and polarizers was of interest. Although the panel had heard of no technology on passivation layers, it was nevertheless a goal to see if any could be found. Other interests in materials included color filters, an area important to western countries because it can be one of the most expensive parts of displays. Other questions concerned where they obtain their glass, what kind of glass they use, if any work has gone on in polymer lightweight or more rugged substrates, and what substrate materials (e.g., polysilicons) were used in high-temperature active matrix technologies. The panel was also alert to any innovative electrochromic technologies in dispersed particles or any innovative uses of conducting polymers in display technology.

The team member responsible for this section was Dr. Patricia Cladis" of AT&T Bell Laboratories. Since she has many years of experience in the physics of liquid crystal materials and display technology, Dr. Cladis was an ideal person to oversee this subject area.

Liquid Crystal and Other Nonemissive Displays

The principal and almost exclusive nonemissive technology these days is liquid crystal display technology, although the panelists had in mind other technologies, such as electrochromic displays or displays from high-speed dispersed particles. In the area of liquid crystal technologies, the panel was interested in activities related to twisted nematic (TN), supertwisted nematic, and pi-cell displays. The panel also wanted to examine ferroelectric and antiferroelectric technologies, and other types of memory materials. In this category, the WTEC panel knew that in Ukraine there was activity on bistable cholesteric liquid crystal displays, which was one reason for choosing Kyyiv as a site to visit. PDLC materials displays were also of interest. WTEC had heard of some active matrix efforts in the FSU, particularly amorphous silicon and polysilicon (thin-film transistor or TFT) technologies. Panelists also were aware of possible MIM (metal-insulator-metal) technologies in Belarus, the team's principal reason for traveling to Minsk. The third area of interest for nonemissive technology was the light valve for projection devices. The panel's goal was to seek possible projection innovations and light sources, optical systems, and unique addressing schemes for liquid crystal spatial light modulators. Finally, the panel wanted information on various support technologies such as backlights, substrates, packaging, interconnects (chip-on glass), and driver technologies, as well as system integration. The team member responsible for overseeing this area of study was Dr. Zvi Yaniv of Advanced Technology Incubator. As the founder of Optical Imaging Systems, the only active matrix display manufacturer in the United States, Dr. Yaniv came with extensive experience in liquid crystal display technology.

Vacuum Fluorescent, Electroluminescent, Field Emission, and Other Emissive Displays

In the area of emissive technology, the panel's interests were electroluminescent (EL) displays, particularly progress in white electroluminescent full-color displays, and especially in the blue ones. Color plasma display panels (PDP), large screens, the use of tiling or projection screen technology, and small displays, such as head-mounted displays, portable instrument displays, and so on, were covered, as were cathode ray tubes, particularly as they appeared in innovative applications.

The team had evidence of development in Moscow of an exciting new e-beam addressed laser system for projection. A principal mission of the emissive display study was to obtain as much information as possible on this innovation. Several sites in Moscow were selected because of this technology. Field emissive (FE) displays, a growing technology in the United States, was a prime target for this group. Before the visit, panelists did not realize the strong advances made by FSU scientists in vacuum fluorescent displays. While it was listed as a site issue, it turned out to be a major find. Light-emitting diodes (LED) and any other emissive technologies that might arise, such as crystalline organic or other kinds of emissive devices, completed the list of topics.

The team member elected to head this study was Christopher Curtin, who has had years of experience in the emissive display industry.

Phosphors and Other Emissive Materials

The panel's interest in emission display materials was primarily in phosphors, including such parameters as particle size control, low-voltage phosphors, high-voltage phosphors, synthesis techniques, deposition techniques, and screening techniques, extending to activation techniques and ion implantation. Progress in materials for blue and white was also important. The panel also sought innovations with polymers for light-emitting diodes and other electroluminous materials.

Finally, the panel looked for excitation sources, such as ultraviolet, electron, or field emission. An eye was kept open for any innovations in the characterization technology of emissive display materials.

The team member responsible for this section was Dr. Jan Talbot of the University of California at San Diego, who is well known for work on phosphor materials.

Infrastructure

Since the panel had little reliable information, the matter of what infrastructure existed in the FSU was perhaps one of the biggest unknowns. Goals included learning of sources for instrumentation and manufacturing equipment, learning the relationships among academic associations, examining support technology, and reviewing standardization of quality and reliability. Dr. James Larimer of NASA, a generalist in flat-panel display technologies, oversaw this section.

Business Structures and Issues

The last but not the least interesting topic was the matter of business structures and issues in the FSU countries. Here the panel was interested in the organization and structure of institutes, as well as interactions with government, industry, and academic-producing amalgamations. The panel sought information on what policies regulate such activities as technology transfer and intellectual property. Who does what in these countries and what is their intent? What efforts have there been toward privatization, and what are the problems associated with it? Dr. Marko Slusarczuk was responsible for this section.


Published: December 1994; WTEC Hyper-Librarian