Liquid crystal mixture having at least two liquid crystalline components, useful for nematic and supertwisted nematic liquid crystal displays, comprises at least one aromatic acetylene compound

摘要

A liquid crystal mixture having two or more liquid crystalline components comprises at least one aromatic acetylene compound. A liquid crystal mixture (I) having two or more liquid crystalline components comprises at least one compound of formula (1). R<11> = 1-12C alkyl, alkoxy or alkenyl optionally having one or two non-+neighboring CH2 groups replaced by -O-, -CHCH-, -CO-, -OCO- or -COO-; R<12> = 1-8C alkyl, optionally substituted by F; L<1>-L<4> = H or F. An Independent claim is included for twisted nematic or supertwisted nematic liquid crystal devices (II) having two support plates and an edge to form a cell containing a nematic liquid crystal mixture having a positive adielectric anisotropy, electrode layers with orientation layers on the inner faces of the support plates, a pitch angle between the long axis of the molecule at the surface of the support plate and the support plate of 0-30 deg and a twist angle of the liquid crystal mixture in the cell from orientation layer to orientation layer of 22.5-600 deg whereby the nematic liquid crystal mixture comprises: (I) 15-80 wt.% of a liquid crystalline component (A) comprising at least one compound having a dielectric anisotropy of greater than ?+1.5; (II) 20-85 w.t% of a liquid crystalline component (B) comprising at least one compound having a dielectric anisotropy of ?-1.5-?+1.5; (III) 0-20 wt.% of a liquid crystalline component (D) comprising at least one compound having a dielectric anisotropy of less than ?-1.5; and (IV) optionally an optically active component (C) in an amount such that the ratio between layer thickness (gap between support plates) and the natural transition height of the chiral nematic liquid crystal mixture is 0.2-1.3, whereby the liquid crystal mixture contains at least one compound of formula (1).