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

• Published in: Nature (London) Vol. 411; no. 6833; pp. 56 - 59
• Main Authors: Chaudhari, P, Lacey, James, Doyle, James, Galligan, Eileen, Lien, Shui-Chi Alan, Callegari, Alesandro, Hougham, Gareth, Lang, Norton D, Andry, Paul S, John, Richard, Yang, Kei-Hsuing, Lu, Minhua, Cai, Chen, Speidell, James, Purushothaman, Sampath, Ritsko, John, Samant, Mahesh, Stöhr, Joachim, Nakagawa, Yoshiki, Katoh, Yoshimine, Saitoh, Yukito, Sakai, Kazumi, Satoh, Hiroyuki, Odahara, Shuichi, Nakano, Hiroki, Nakagaki, Johji, Shiota, Yasuhiko
• Format: Journal Article
• Language: English
• Published: London Nature Publishing 03.05.2001; Nature Publishing Group
• Subjects: Alignment; Atoms & subatomic particles; Crystals; Deposition; Display devices, liquid-crystal devices; Displays; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Ion beams; Laptop; LCDs; Liquid crystal displays; Liquid crystals; Liquids; Manufacturing; Optical elements, devices, and systems; Optics; Physics; Rubbing; Alignment; Liquid crystal devices; Molecular orientation; Experimental study; Twisted nematic state; Ion beams
• ISSN: 0028-0836; 1476-4687
• DOI: 10.1038/35075021

The technique used to align liquid crystals-rubbing the surface of a substrate on which a liquid crystal is subsequently deposited-has been perfected by the multibillion-dollar liquid-crystal display industry. However, it is widely recognized that a non-contact alignment technique would be highly desirable for future generations of large, high-resolution liquid-crystal displays. A number of alternative alignment techniques have been reported, but none of these have so far been implemented in large-scale manufacturing. Here, we report a non-contact alignment process, which uses low-energy ion beams impinging at a glancing angle on amorphous inorganic films, such as diamond-like carbon. Using this approach, we have produced both laptop and desktop displays in pilot-line manufacturing, and found that displays 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 random network model of atomic arrangement in the inorganic films. Order is induced by exposure to an ion beam because unfavourably oriented rings of atoms are selectively destroyed. The planes of the remaining rings are predominantly parallel to the direction of the ion beam.