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P‐83: Liquid Crystal Alignment on Substrates Treated with the Plasma Flux: Static and Dynamic Regimes of Irradiation
Author(s) -
Yaroshchuk Oleg,
Kravchuk Ruslan,
Dobrovolskyy Andriy,
Lee C.D.,
Liu P.C.,
Qiu Liou,
Lavrentovich Oleg D.
Publication year - 2004
Publication title -
sid symposium digest of technical papers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.351
H-Index - 44
eISSN - 2168-0159
pISSN - 0097-966X
DOI - 10.1889/1.1831040
Subject(s) - irradiation , materials science , plasma , perpendicular , optics , flux (metallurgy) , beam (structure) , polymer , composite material , physics , geometry , mathematics , quantum mechanics , nuclear physics , metallurgy
In this paper, we present the new results related to LC alignment on the substrates obliquely treated with a “sheet” of accelerated Ar + plasma generated by an anode layers thruster (ALT). The substrates of organic (polymers) and inorganic (glass, DLC, SiO 2 , etc.) origin were treated with the plasma flux in static and dynamic regime (unidirectional translation perpendicularly to plasma “sheet”). For LCs with Δ∍<0 , in both regimes, we observed two aligning modes, with the easy axis confined to the plane of plasma incidence (mode 1) or perpendicular to this plane (mode 2). In the 1 st aligning mode the LC pretilt angle is not equal to zero and can be varied with the incidence angle of plasma beam and the irradiation dose. The uniformity of pretilt angle is better in the dynamic regime. With the increase of irradiation dose, the alignment transition from the 1 st to the 2 nd mode occurs. For the LC mixtures with Δ∍<0 , used for VA LCD, only the 1 st mode alignment (uniform over the whole substrate) is realized. It occurs at low and even at the relatively high irradiation doses, which cause the 2 nd mode alignment for the LCs with δ∍>0. The pretilt angle achieves values as high as 30° and can be controlled by the irradiation dose and by the incidence angle of plasma beam. The 2 nd alignment mode is observed at high irradiation doses and only in the static regime of irradiation. It occurs in the central, most intensive part, of the plasma “sheet”, while the periphery part shows the 1 st mode. The areas of the 1 st and the 2 nd mode are separated with the narrow transition area showing multidomain (two‐fold degenerate) LC alignment. The easy axis in these domains is turned by about ±45° with respect to the alignment direction in the 1 st mode area. The alignment transition 1 st mode — two‐fold degenerate alignment — 2 nd mode observed for LC with δ∍<0 is quite similar to the one earlier described for vapor deposition alignment. In the dynamic irradiation regime, for both types of LC, uniform alignment on the substrates as big as 15×15 cm is realized.