Liquid crystalline medium with positive dielectric anisotropy, useful for electro optical purposes such as electro optical liquid crystal display, comprises 1,2-difluoroethene compound

摘要

Liquid crystalline medium (A) with positive dielectric anisotropy based on a mixture of compounds, comprises one or more 1,2-difluoroethene compound (I). Liquid crystalline medium (A) with positive dielectric anisotropy based on a mixture of compounds, comprises one or more 1,2-difluoroethene compound of formula (I). R 1> : halogenated or unsubstituted 1-15C alkyl- or alkoxy residue (where one or more CH 2-group is replaced by -Ctriple boundC-, -CH=CH-, -O-, -CO-O- or -O-CO-, and O atoms are not connected directly together); A 1> : -cyclohexane-, 4 heterocyclic compound e.g. -dioxane- or -pyrimidine-, -fluoro-benzene-, -1,3-difluoro-benzene-, -phenyl- or bicyclic compound of formula (a); Z 1>, Z 2> : a single bond, -Ctriple boundC-, -CF=CF- (preferred), -CH=CH-, -CF 2O- or -CH 2CH 2-; X : F, Cl, CN, SF 5 or halogenated or unsubstituted 1-15C alkyl- or alkoxy (where one or more CH 2-group is replaced by -Ctriple boundC-, -CH=CH-, -O-, -CO-O- or -O-CO-, and the O atoms are not connected directly together); L 1>-L 6> : H or F; and m : 0-1. Independent claims are included for: (1) an electro optical liquid crystal display comprising (A); and (2) a difluoroethene compound of formula (Ia). m : 1-2. [Image] [Image].