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

Abstract

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.

Competition of terrace and step-edge sputtering under oblique-incidence ion impact on a stepped Pt(111) surface

“…The phenomenon is of immediate interest to the field of the nanopatterning of thin films [8,9] with applications, e.g. as a template for the adsorption of large molecules [10], for the manipulation of magnetism [11] or for tuning the chemical reactivity of catalytically active surfaces [12].…”

Bifunctional ITO layer with a high resolution, surface nano-pattern for alignment and switching of LCs in device applications

“…Although rubbing is a simple and inexpensive method, it has many intrinsic drawbacks such as generation of electrostatic charges, contamination from rubbing debris and high temperatures (up to ca 250 1C). As alternatives to the rubbing process, noncontact methods such as photo-alignment [2][3][4][5] and ion-beam irradiation 6 have been used but they also have critical drawbacks associated with controlling the orientation of photoswitchs on the surface and low anchoring energies. 7 Indium-tin oxide (ITO) has been widely used as an electrode for LC display because of its low electrical resistance and high transmittance in the visible range of the optical spectrum.…”

Localized subsurface modification of materials using micro-low-energy multiple ion beamlets

“…The interaction of low energy ion beams with matter is quite different from that of high energy ion beams. High energy ion beams are able to sputter, 4 channel, 5 deposit deep inside, and backscatter from substrates 6 etc because of its higher range inside the materials, 7,8 patterning, and generation of internal subsurface excitations [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27] etc. Since low energy ion beams cannot penetrate deep inside the substrate therefore its interaction is mainly limited to surface and sub-surface layers.…”

“…In reference 14 of the manuscript, propagation of ripples has been observed for pyrochlore sample with 30 kV Ga + ion beam. Some of the potential applications that people have investigated are: manipulating magnetism, 15 for the ordered adsorption of large molecules, 16 for tuning the chemical reactivity of catalytically active surfaces, 17 for optoelectronic devices, 18 etc. (2) Nano gas bubble formation in metals: bubbles of rare gases are formed inside a metal when rare gas atoms are deposited on it and form an interesting nanosystem.…”