Electrooptical liquid crystal system

US5958290A · kind A · utility

Assignee

• Merck Patent GmbH · DE

Inventors

• David Coates · Bishop's Stortford, GB
• Shirley Ann Marden · Poole, GB
• Graham Smith · Poole, GB
• Ulrich Finkenzeller · Plankstadt, DE
• Volker Reiffenrath · Roßdorf, DE
• Reinhard Hittich · Seeheim-Jugenheim, DE
• Stefan Wilhelm · Unterhaching, DE

Key dates

• Filing date: Feb 23, 1995
• Grant date: Sep 28, 1999
• Expiry date: Feb 23, 2015

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C09K19/544
• WIPO field: Basic materials chemistry
• WIPO sector: Chemistry

Abstract

The invention relates to an electrooptical liquid crystal system PA1 which contains a dielectrically positive liquid crystal mixture and a further optically transparent medium between 2 electrodes which are optionally applied to substrate sheets, PA1 whose liquid crystal molecules in the switched-off state have an irregular orientation, PA1 in which one of the refractive indices of the liquid crystal mixture essentially agrees with the refractive index of the matrix n.sub.M and/or in which the quotient of the mass of the liquid crystal mixture and of the mass of the optically transparent medium is 1.5 or more and, PA1 which, independently of the polarization of the incident light, has a reduced transmission in one of the two switch states compared to the other state and PA1 whose liquid crystal mixture contains one or more compounds of the formula I ##STR1## in which Q.sup.1 is ##STR2## are independently of one another trans-1,4-cyclohexylene, 1,4-phenylene, 2-fluoro-1,4-phenylene, 3-fluoro-1,4-phenylene and one of A.sup.1 and, if present, A.sup.2, is also pyridine-2,5-diyl, pyrimidine-2,5-diyl, 1,3-dioxane-2,5-diyl, tetrahydropyran-2,5-diyl or naphthalene-2,6-diyl, PA1 Z.sup.1 and…