Atomic-beam alignment of inorganic materials for liquid-crystal displays

The technique used to align liquid crystals-rubbing the surface of a substr ate on which a liquid crystal is subsequently deposited(1-3)-has been perfe cted by the multibillion-dollar liquid-crystal display industry. However, i t is widely recognized that a non-contact alignment technique would be high ly desirable for future generations of large, high-resolution liquid-crysta l displays. A number of alternative alignment techniques have been reported (4-7), but none of these have so far been implemented in large-scale manufa cturing. Here, we report a non-contact alignment process, which uses low-en ergy ion beams impinging at a glancing angle on amorphous inorganic films, such as diamondlike carbon. Using this approach, we have produced both lapt op and desktop displays in pilot-line manufacturing, and found that display s of higher quality and reliability could be made at a lower cost than the rubbing technique. The mechanism of alignment is explained by adopting a ra ndom network model of atomic arrangement in the inorganic films. Order is i nduced by exposure to an ion beam because unfavourably oriented rings of at oms are selectively destroyed. The planes of the remaining rings are predom inantly parallel to the direction of the ion beam.