Chiral nematic liquid crystal mixture, used in display, e.g. for laptop, contains 4-cyclohexylbenzonitrile and 1-(diphenylyl)-2-(2,(6)-(di)fluoro-phenyl)-acetylene compounds

摘要

In chiral nematic liquid crystal (LC) mixture with positive dielectric anisotropy, consisting of LC components comprising 20-90 wt.% A (dielectric anisotropy ( DELTA iota ) over +1.5), 10-80 wt.% B ( DELTA iota -1.5 to +1.5) and 0-20 wt.% C ( DELTA iota less than -1.5) and an optically active component D, A contains mixture of 4-cyclohexylbenzonitrile(s) (IA) and 1-(diphenylyl)-2-(2,(6)-(di)fluoro-phenyl)-acetylene(s) (IB). Nematic LC mixture consists of 20-90 wt.% LC component A of compound(s) with a dielectric anisotropy of over +1.5, 10-80 wt.% LC component B of compound(s) with a dielectric anisotropy between -1.5 and +1.5, 0-20 wt.% LC component C with a dielectric anisotropy less than -1.5 and an optically active component D in such an amount that the ratio between the film thickness (space between the plates) and natural pitch of the chiral nematic LC mixture is about 0.2-1.3. The novelty is that component A contains a mixture of 4-(trans-4-alkenylcyclohexyl)benzonitrile(s) (IA) and 1-(4'-substituted-diphenylyl)-2-(4-substituted.-2-fluoro- or -2,6-difluoro-phenyl)-acetylene(s) (IB) of the formulae; R3 = 2-7 carbon (C) alkenyl; R1, R2 = 1-12 C alkyl, alkoxy or alkenyl, in which 1 or 2 non-adjacent CH2 groups may by replaced by -O-, -CH=CH-, -CO-, -OCO- or -COO- without directly linked O atoms; L = hydrogen (H) or fluorine (F) . An Independent claim is also included for (super) twisted nematic (TN or STN) liquid crystal (LC) displays filled with this LC mixture.