The invention relates to a liquid-crystalline medium having negative dielectric anisotropy comprising one or more compounds of formula I ##STR00001##
and
one or more compounds selected from the group of the compounds of the formulae IIA, IIB and IIC, ##STR00002##
wherein the groups and parameters have the meanings indicated in claim 1, to a guest-host liquid crystal medium derived therefrom comprising one or more dichroic dyes and the use of said medium in devices such as light shutters, switchable windows, switchable mirrors and guest-host displays. The invention further relates to devices containing the liquid crystalline medium according to the invention.

The invention relates to a liquid-crystalline medium having negative dielectric anisotropy comprising one or more compounds of formula I ##STR00001##
and
one or more compounds selected from the group of the compounds of the formulae IIA, IIB and IIC, ##STR00002##
wherein the groups and parameters have the meanings indicated in claim 1, to a guest-host liquid crystal medium derived therefrom comprising one or more dichroic dyes and the use of said medium in devices such as light shutters, switchable windows, switchable mirrors and guest-host displays. The invention further relates to devices containing the liquid crystalline medium according to the invention.

An object of the present invention is to provide a polarizer having a high degree of alignment and an image display device including the polarizer. The polarizer according to the embodiment of the present invention is a polarizer which is formed of a polarizer-forming composition containing a polymer liquid crystal compound and a dichroic material, in which the polymer liquid crystal compound is a thermotropic liquid crystal and a crystalline polymer, and the polymer liquid crystal compound and the dichroic material are horizontally aligned.

A compound represented by Formula (1) or (11) below,

X-A.sup.1-(N═N-A.sup.2).sub.n-N═N-A.sup.3-Y  (1) (in Formula (1), -A.sup.1- and -A.sup.2- each independently represent an unsubstituted or substituted divalent group of an aromatic heterocyclic ring including one or more S atoms wherein atoms constituting the aromatic heterocyclic ring other than a carbon atom are not adjacent to one another, an unsubstituted or substituted divalent group of a benzisothiazole ring, or an unsubstituted or substituted divalent group of an aromatic hydrocarbon ring; -A.sup.3- represents an unsubstituted or substituted divalent group of an aromatic hydrocarbon ring; —X represents a branched alkyl, alkoxy, or alkylsulfanyl group having 3 or more carbon atoms; —Y represents a monovalent organic group; n represents 1, 2, or 3; when n is 2 or 3, a plurality of -A.sup.2-'s may be identical to or different from one another; and -A.sup.1- and -A.sup.2- do not represent an unsubstituted or substituted divalent group of an aromatic hydrocarbon ring at the same time),

X-A.sup.41-(N═N-A.sup.42).sub.n-N═N-A.sup.43-Y  (11) (in Formula (11), at least one -A.sup.42- represents an unsubstituted or substituted divalent group of an aromatic heterocyclic ring including one or more S atoms; -A.sup.41- and -A.sup.43- each independently represent an unsubstituted or substituted divalent group of an aromatic hydrocarbon ring; —X represents a branched alkyl, alkoxy, or alkylsulfanyl group having 3 or more carbon atoms; —Y represents a monovalent organic group; n represents 1, 2, or 3; and when n is 2 or 3, a plurality of -A.sup.42-'s may be identical to or different from one another).

A liquid crystal composition includes a component A composed of one or more liquid crystals with negative dielectric anisotropy and a component B composed of one or more compounds selected from a general formula I, where the optical anisotropy of the liquid crystal composition is larger than 0.14. The elastic coefficient of a liquid crystal system is adjusted by introducing a bi-mesogenic compound into a negative liquid crystal or a negative liquid crystal mixture. When the liquid crystal composition is used for the dimming device, the minimum light transmittance of the dimming device in the dark state can be significantly reduced, the adjustment range of the light transmittance in the light state and the dark state can be expanded, and the haze in the dark state can be increased, thereby broadening the use range.

##STR00001##

A liquid crystal composition includes a component A composed of one or more liquid crystals with negative dielectric anisotropy and a component B composed of one or more compounds selected from a general formula I, where the optical anisotropy of the liquid crystal composition is larger than 0.14. The elastic coefficient of a liquid crystal system is adjusted by introducing a bi-mesogenic compound into a negative liquid crystal or a negative liquid crystal mixture. When the liquid crystal composition is used for the dimming device, the minimum light transmittance of the dimming device in the dark state can be significantly reduced, the adjustment range of the light transmittance in the light state and the dark state can be expanded, and the haze in the dark state can be increased, thereby broadening the use range.

##STR00001##

A dye composition dissolvable within a liquid crystal host device (including: polymer dispersed liquid crystal, polymer network liquid crystal, polymer stabilized liquid crystal, liquid crystal displays and similar devices), comprising eutectic mixtures of dichroic metallomesogen molecules. The aforesaid metallomesogen molecules comprise chromophore groups synthesized by physical and chemical mixing methods.

A dye composition dissolvable within a liquid crystal host device (including: polymer dispersed liquid crystal, polymer network liquid crystal, polymer stabilized liquid crystal, liquid crystal displays and similar devices), comprising eutectic mixtures of dichroic metallomesogen molecules. The aforesaid metallomesogen molecules comprise chromophore groups synthesized by physical and chemical mixing methods.

The present invention relates to liquid-crystalline media comprising one or more pleochroic dyes and one or more compounds selected from the group of compounds of formulae I, II and III,

##STR00001##

in which the parameters have the meaning indicated in Claim 1, and to components comprising these media for high-frequency technology, in particular phase shifters and microwave array antennas.

The present invention relates to liquid-crystalline media comprising one or more pleochroic dyes and one or more compounds selected from the group of compounds of formulae I, II and III,

##STR00001##

in which the parameters have the meaning indicated in Claim 1, and to components comprising these media for high-frequency technology, in particular phase shifters and microwave array antennas.