In-plane switching liquid crystal display with high voltage holding ratio

摘要

Electrooptical liquid crystal display (LCD) has an orientation film with a significant field component parallel to the liquid crystal (LC) layer and an LC medium with positive dielectric anisotropy. The novelty is that the medium contains (a) mesogenic compound(s) containing a 3,4-difluorophenyl (Ph.2F) group and (b) mesogenic compound(s) of formula R<1>-(A<1>-Z<1>)m-A<2>-R<2> (I); in which R<1>, R<2> = 1-12 C alk(en)yl, optionally mono-substituted by cyano (CN) or trifluoromethyl (CF3) or at least mono-substituted by halogen, in which one or more CH2 groups may be replaced by oxygen (-O-), sulphur (-S-), 1,3-cyclobutylene, carbonyl (-CO-), carboxyl (-CO-O- or -O-CO-) or carbonate (-O-CO-O-) groups, without directly linked O atoms; A<1>, A<2> = (a) trans-1,4-cyclohexylene (Cyc) or 1,4-cyclohexenylene, in which 1 or more non-adjacent CH2 groups may be replaced by -O- and/or -S-, (b) 1,4-phenylene (Phe), in which 1 or 2 CH groups may be replaced by nitrogen (N) or (c) 1,4-bicyclo(2,2,2)-octylene, piperidin-1,4-diyl, naphthalen-2,6-diyl, decahydronaphthalen-2,6-diyl or 1,2,3,4-tetrahydronaphthalen-2,6-diyl and groups (a) and (b) may be mono- or di-substituted by fluorine (F); Z<1> = -CO-O-, -O-CO-, -CH2O-, -OCH2-, -CH2CH2-, -CH=CH-, -C?=C-, a single bond, -(CH2)4- or -CH=CH-CH2CH2-; m = 1, 2 or 3.