The invention relates to liquid-crystalline media which can be used, in particular, for electro-optical displays having active-matrix addressing based on the ECB effect and for IPS (in-plane switching) displays or FFS (fringe field switching) displays.

The invention relates to a liquid-crystalline medium which comprises at least one compound of the formula I,

##STR00001## in which R.sup.1 and R.sup.1* each, independently of one another, denote an alkyl or alkoxy radical having 1 to 15 C atoms, where, in addition, one or more CH.sub.2 groups in these radicals may each be replaced, independently of one another, by

##STR00002##

in such a way that O atoms are not linked directly to one another, and in which, in addition, one or more H atoms may be replaced by halogen, A.sup.1 denotes

##STR00003## L.sup.1 denotes F, Cl, CF.sub.3, OCF.sub.3 or CHF.sub.2,
and to the use thereof for electro-optical purposes, in particular for shutter glasses, 3D applications, in TN, PS-TN, STN, TN-TFT, OCB, IPS, PS-IPS, FFS, PS-FFS and PS-VA-IPS displays.

Provided are a liquid crystal composition satisfying at least one of characteristics such as high maximum temperature, low minimum temperature, small viscosity, suitable optical anisotropy and large dielectric anisotropy, or having a suitable balance regarding at least two of the characteristics, and an AM device including the composition.

The liquid crystal composition contains a quencher as a first additive, and may contain a specific compound having large negative dielectric anisotropy as a first component, a specific compound having high maximum temperature or small viscosity as a second component, or a specific compound having a polymerizable group as a second additive.

The invention relates to a liquid-crystalline medium which comprises at least one compound of the formula I,

##STR00001##

in which R.sup.1, R.sup.1*, rings A and B, Z.sup.1, L.sup.1, L.sup.2, a and b have the meanings indicated in Claim 1, and to the use thereof for an active-matrix display, in particular based on the VA, PSA, PS-VA, PALC, FFS, PS-FFS, IPS or PS-IPS effect.

The present invention relates to polymerizable compounds, to processes and intermediates for the preparation thereof, to liquid-crystal (LC) media comprising them, and to the use of the polymerizable compounds and LC media for optical, electro-optical and electronic purposes, in particular in LC displays, especially in LC displays of the polymer sustained alignment type.

Material comprising a ferroelectric nematic phase, the material are disclosed. The material can include a mixture comprising first molecules and second molecules. At least one of a fluid of the first molecules and a fluid of the second molecules exhibits a ferroelectric nematic phase. The first molecules and second molecules are miscible. The first molecules can induce a polar orientational order of said second molecules.

Provided are a liquid crystal compound satisfying at least one of physical properties such as high stability to heat or light, high maximum temperature of a liquid-crystal phase, low minimum temperature thereof, small viscosity, suitable optical anisotropy, large dielectric anisotropy and good compatibility with other liquid-crystal compounds, a liquid crystal composition containing the compound and a liquid crystal display device including the composition.

A compound is represented by formula (1), a liquid crystal composition contains the compound and a liquid crystal display device includes the composition.

##STR00001##

In formula (1), Ra and Rb are fluorine or alkyl; A.sup.0, A.sup.1 and A.sup.2 are 1,4-phenylene; Z.sup.1 and Z.sup.2 are a single bond or alkylene; one of Y.sup.1 and Y.sup.2 is fluorine, and the other is hydrogen; Rc is alkyl; and a and b are independently 0, 1, 2 or 3, and a sum of a and b is 0, 1, 2 or 3.

The invention relates to a liquid-crystalline medium, preferably having a nematic phase and dielectric anisotropy of 0.5 or more, which comprises one or more compounds of formula Y

##STR00001##

in which the parameters have the meanings given in the text,
to the use thereof in an electro-optical display, particularly in an active-matrix display based on the IPS or FFS effect, to displays of this type which contain a liquid-crystalline medium of this type, and to the use of the compounds of formula Y for the improvement of the transmission and/or response times of a liquid-crystalline medium which comprises one or more additional mesogenic compounds.

A liquid crystal element includes a pair of substrates disposed to face each other, a liquid crystal layer disposed between the pair of substrates, and a liquid crystal alignment layer provided on each of the liquid crystal layer sides of the pair of substrates. The liquid crystal layer includes a compound having an alkenyl structure and a compound having a terphenyl ring structure, or includes a compound having an alkenyl structure and a terphenyl ring structure in the same molecule, and the liquid crystal alignment layer is a layer comprising a liquid crystal alignment agent containing a polymer (P) which has at least one selected from the group consisting of a radical polymerizable group, a photoinitiator group, a nitrogen-containing heterocyclic ring (excluding imide rings in polyimides), an amino group and a protected amino group.

Described is a liquid crystal composition which satisfies at least one of such characteristics as high upper limit temperature of the nematic phase, low lower limit temperature of the nematic phase, low viscosity, adequate optical anisotropy, large negative dielectric anisotropy, high resistivity, high stability to ultraviolet light and high stability to heat, or which has an adequate balance between at least two of the above-mentioned characteristics. Also described is an AM element having a short response time, high voltage holding ratio, high contrast ratio, long life and the like. The liquid crystal composition contains a specific compound having a large negative dielectric anisotropy and a low lower limit temperature as a first component, a specific compound having a low viscosity or a high upper limit temperature as a second component, and a specific compound having a polymerizable group as a third component. The AM element contains the composition.