STN liquid-crystal display
AssigneeMerck Patent Gesellschaft
InventorsHarald Hirschmann, Sven Schüpfer, Marcus Reuter, Volker Reiffenrath, Sabine Schoen
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Abstract
Supertwist liquid-crystal displays (SLCDs) with outstanding properties are obtained if the nematic liquid-crystal mixtures used therein comprise one or more compounds of the formula IA and one or more compounds of the formula IB Ra is alkyl, alkoxy, alkenyl or alkenyloxy having 1 to 12 carbon atoms, Rb is alkyl or alkoxy having 1 to 5 carbon atoms, Z is —COO —CH2CH2— or a single bond, and are each, independently of one another, and one of the rings may alternatively be R3 is an alkenyl group having 2 to 7 carbon atoms, R4 is as defined for Ra in the formula IA, and c is 0 or 1.
Claims19
A supertwist liquid-crystal display comprising:
- two outer plates which, together with a frame, form a cell,
- electrode layers with alignment layers on the insides of the outer plates,
- a pretilt angle between the longitudinal axis of the molecules at the surface of the outer plates and the outer plates of from about 1 degree to 30 degrees, and
- a twist angle of the liquid-crystal mixture in the cell from alignment layer to alignment layer with a value of between 100° and 600°, and
- a nematic liquid-crystal mixture of positive dielectric anisotropy which is present in the cell, comprising:
- a) 5-90% by weight of a liquid-crystalline component A consisting of one or more compounds having a dielectric anisotropy of greater than +1.5;
- b) 10-80% by weight of a liquid-crystalline component B consisting of one or more compounds having a dielectric anisotropy of between −1.5 and +1.5;
- c) 0-20% by weight of a liquid-crystalline component D consisting of one or more compounds having a dielectric anisotropy of below −1.5;
- and
- d) an optically active component C in such an amount that the ratio between the layer thickness and the natural pitch of the chiral nematic liquid-crystal mixture is from about 0.2 to 1.3,
- wherein the liquid-crystal mixture comprises one or more compounds of the formula IA
- in which
- Ra is alkyl, alkoxy, alkenyl or alkenyloxy having 1 to 12 carbon atoms,
- Rb is alkyl or alkoxy having 1 to 5 carbon atoms,
- Z is —COO—, —CH2CH2— or a single bond, and
- are each, independently of one another,
- and one of the rings
- may alternatively be
- and component B comprises one or more compounds of the formula IB
- in which
- R3 is an alkenyl group having 2 to 7 carbon atoms,
- R4 is as defined for Ra in the formula IA, and
- c is 0 or 1.
A liquid-crystal mixture comprising:
- a) 5-90% by weight of a liquid-crystalline component A consisting of one or more compounds having a dielectric anisotropy of greater than +1.5;
- b) 10-80% by weight of a liquid-crystalline component B consisting of one or more compounds having a dielectric anisotropy of between −1.5 and +1.5;
- c) 0-20% by weight of a liquid-crystalline component D consisting of one or more compounds having a dielectric anisotropy of below −1.5;
- and
- d) an optically active component C in such an amount that the ratio between the layer thickness and the natural pitch of the chiral nematic liquid-crystal mixture is from about 0.2 to 1.3,
- wherein the liquid-crystal mixture comprises one or more compounds of the formula IA
- in which
- Ra is alkyl, alkoxy, alkenyl or alkenyloxy having 1 to 12 carbon atoms,
- Rb is alkyl or alkoxy having 1 to 5 carbon atoms,
- Z is —COO—, —CH2CH2— or a single bond, and
- are each, independently of one another,
- and one of the rings
- may alternatively be
- and component B comprises one or more compounds of the formula IB
- in which
- R3 is an alkenyl group having 2 to 7 carbon atoms,
- R4 is as defined for Ra in the formula IA, and
- c is 0 or 1.
Dependencies are inferred from the claim text.