General Competition (November 1993)

Optically Controlled Alignment Materials for Liquid-Crystal Displays

Sponsor: Elsicon, Inc. (acquired technologyfrom Alliant Techsystems, Research Center)

• Project Performance Period: 2/1/1994 - 1/31/1997
• Total project (est.): $3,042,115.00
• Requested ATP funds: $1,670,628.00

Liquid-crystal displays (LCDs) are ubiquitous, found on appliances from washing machines and ovens to laptop computers. The world market is growing rapidly and is expected to be greater than $5 billion by 1997. This is despite the fact that large LCDs are rather tricky to manufacture: current manufacturing yields of active-matrix liquid-crystal displays, for example, are only 15 to 50 percent. One of the more difficult problems is that virtually all liquid crystal applications require that the crystals be uniformly aligned. This is done in a mechanical process called buffing. A fibrous cloth is rubbed against a thin polymer film next to the liquid crystal medium, causing the crystals to align in the direction of motion. Researchers recently discovered that they could align liquid crystal cells optically by shining polarized light through particular polymer substrates doped with dyes. Not only is this technique simpler and more reliable than mechanical buffing, by using masking or other techniques optical aligning can orient liquid crystals in high-resolution patterns, something quite impossible with mechanical buffing. And while the liquid crystals seem to remain in the imposed alignment indefinitely, they also can be realigned almost instantly by repeating the process. Optical alignment is expected to be particularly important for the growing active-matrix LCD market, where extremely low yields are associated with problems introduced by mechanical buffing. The basic technique, however, might be applied to a large number of other applications including large, "electrodeless" LCDs for projection HDTV systems, erasable optical data storage, and optical signal processing devices. For practical applications, optically aligned LCDs must use low optical energy, have long-term thermal and optical stability, have high optical quality, and be compatible with existing LCD systems. The Alliant project will be directed at developing the generic optical alignment technology to meet these needs.

For project information:

Rod Bitz, (612) 931-5413

ATP Project Manager

Carlos Grinspon, (301) 975-4448
carlos.grinspon@nist.gov