The invention relates to a liquid-crystalline medium based on a mixture of polar compounds having negative dielectric anisotropy (Δe), which contains at least one compound selected from the group of compounds of the formula I, II A and II B and at least one compound of the formula I* in which R0, R1, R2, R1*, X1, X2, A1, A1*, A2*, Z1, Z1*, Z2*, L1*, L2*, p, q, v, m and m* are as defined in Claim 1, and to the use thereof for an active-matrix display based on the ECB, VA, PS-VA, FFS, PALC or IPS effect.

Liquid Crystalline Medium

The use of a certain class of liquid crystal materials that exhibit a smectic C phase allows the production of a bistable liquid crystal display element. Such bistable display elements promote the use of matrix addressing for liquid crystal based elements in a display.

Smectic liquid crystals

The invention is to provide a liquid crystal composition that satisfies at least one of characteristics such as a high maximum temperature of a nematic phase, a low minimum temperature of a nematic phase, a small viscosity, a large optical anisotropy, a large positive dielectric anisotropy, a large specific resistance, a large elastic coefficient, a high stability to ultraviolet light and heat, or that is suitably balanced between at least two of the characteristics. As the liquid crystal display device containing the compositions is to provide an AM device that has a short response time, a large voltage holding ratio, a large contrast ratio, a long service life and so forth, thus it can be used for the liquid crystal projector, liquid crystal television and so forth.

Liquid crystal composition and liquid crystal display device

Disclosed are: a liquid crystal composition, which satisfies at least one property selected from a high upper-limit temperature in a nematic phase, a low lower-limit temperature in a nematic phase, a low viscosity, high optical anisotropy, high dielectric anisotropy, a high specific resistivity, high stability to ultraviolet ray, high stability to heat and the like, or which has an adequate balance between at least two properties selected from the above-mentioned properties; and an AM element having a short response time, a high voltage holding ratio, a high contrast ratio, a long service life and the like. Specifically disclosed are: a liquid crystal composition which comprises a specific pentacyclic compound having high optical anisotropy and high dielectric anisotropy as the first component, a specific compound having a low viscosity as the second component, and a specific tetracyclic compound having a high upper-limit temperature as the third component, and which has a nematic phase; and a liquid crystal display element comprising the composition.

Liquid crystal composition and liquid crystal display element

Liquid crystal (LC) media based on a mixture of polar compounds having negative dielectric anisotropy, their use in electro-optical displays, especially those having active matrix addressing based on the ECB (electrically controlled birefringence) or VA (vertically aligned) mode or similar modes, and LC displays of these types, are described.

Liquid crystal medium

A novel cyclohexane derivative having a good stability, a low viscosity and a large dielectric aniostropy value and a liquid crystal composition containing the same are provided, which derivative is expressed by the formula ##STR1## wherein R represents an alkyl group of 1 to 10 carbon atoms; A represents hydrogen, halogen or cyano group; l represents 1 or 2; and m represents 0 or 1.

Cyclohexane derivative and liquid crystal composition containing the same

New liquid crystal compounds having a low viscosity and nevertheless having a high transparent point and a broad nematic temperature range, and liquid crystal compositions containing the same are provided. The compounds are liquid-crystalline halogenobenzene derivatives expressed by the general formula ##STR1## wherein R represents an alkyl group having 1 to 10 carbon atoms; ##STR2## and X and Y each are H, F or Cl, at least one of X and Y being F or Cl.

Liquid-crystalline halogenobenzene derivatives

Benzene derivatives useful as a component of liquid crystal compositions are provided which are expressed by the general formula ##STR1## wherein R represents a hydrogen atom or an alkyl group of 1 to 10 carbon atoms; R' represents a hydrogen atom, an alkyl group of 1 to 10 carbon atoms or an alkoxy group of 1 to 10 carbon atoms; and ##STR2## represents ##STR3## The derivatives exhibit small values of positive dielectric anisotropy; have broader liquid crystal temperature ranges; and in particular, have higher liquid crystalline-transparent points and yet have lower viscosities.

Liquid crystal benzene derivatives

Liquid crystal materials for liquid crystal display, having a large negative dielectric anisotropy and maintaining a liquid crystal state at a broad temperature range including room temperature are provided. These materials contain novel compounds expressed by the general formula (I) ##STR1## wherein X represents ##STR2## Y represents ##STR3## R1 and R3 each represent an alkyl group or an alkyloxy group of 1-10 carbon atoms; R2 and R4 each represent an alkyl group of 1-10 carbon atoms; but compounds wherein ##STR4## are excluded.

Liquid crystal 2,3-dicyano-hydroquinone derivatives

Novel nematic liquid crystal compounds having a broad nematic temperature range and a positive dielectric anisotropy by themselves, that is, p-cyanophenyl 4-alkyl-4'-biphenylcarboxylates wherein the alkyl is a straight chain alkyl group having 4-8 carbon atoms or a branched alkyl group having 4-7 carbon atoms and having methyl group as branched group, and a method for preparing the same are provided. Further, novel nematic liquid crystal compositions having a broader nematic temper range i.e. a sufficiently lower nematic limit and a sufficiently higher upper nematic limit is provided by using said compounds.

Sugimori Shigeru

Papers

Cyclohexane derivative and liquid crystal composition containing the same

Liquid-crystalline halogenobenzene derivatives

Liquid crystal benzene derivatives

Liquid crystal 2,3-dicyano-hydroquinone derivatives

P-cyanophenyl 4-alkyl-4'-biphenylcarboxylate, method for preparing same and liquid crystal compositions using same