A means is a compound represented by formula (1) , a liquid crystal composition containing the compound, and a liquid crystal display device including the composition.

##STR00001##

In formula (1), R.sup.1 and R.sup.2 are independently alkyl having 1 to 15 carbons or the like; ring A.sup.1, ring A.sup.2 and ring A.sup.3 are independently 1,4-cyclohexylene, 1,4-phenylene or the like; and Z.sup.1, Z.sup.2 and Z.sup.3 are independently a single bond or the like.

The present application relates to mixtures which have liquid-crystalline properties. The application furthermore relates to the use of the mixtures in devices which regulate the transmission of light through an area element.

The invention relates to dielectrically positive liquid crystalline media comprising a compound of formula I ##STR00001##
wherein the parameters have the meaning given in claim 1 and to liquid crystal displays comprising these media, especially to active matrix displays and in particular to TN and IPS mode displays.

Provided is a liquid crystal composition, comprising: one or more compounds of general formula I accounting for 1-30% of the total weight of the liquid crystal composition; one or more compounds of general formula II accounting for 1-30% of the total weight of the liquid crystal composition; one or more compounds of general formula III accounting for 1-20% of the total weight of the liquid crystal composition; and one or more compounds of general formula IV accounting for 30-80% of the total weight of the liquid crystal composition. The liquid crystal composition has at least one of the following properties: a large specific resistance, a high voltage holding ratio, a suitable optical anisotropy, a large dielectric anisotropy, a small viscosity, a low threshold voltage, etc., and is also green and environmentally friendly. The liquid crystal composition is suitable for use in a liquid crystal display device, enabling the liquid crystal display device to have the following properties: a high voltage holding ratio, a short response time, a high contrast ratio, a low energy consumption, and being green and environmentally friendly, etc. ##STR00001##

The purpose of the invention is to control, by using a colorless alignment control monomer, the alignment of liquid crystal molecules of a liquid crystal display element that does not include an alignment film, and to provide a liquid crystal composition with which the colorless alignment control monomer exhibits excellent compatibility. The invention uses a liquid crystal display element that comprises an alignment control monomer including an aromatic ester that undergoes photo-Fries rearrangement by light irradiation, and that employs a liquid crystal composition having a positive dielectric anisotropy. The invention also uses the liquid crystal composition.

There is provided a liquid crystal composition which has favorable characteristics and excellent characteristic balance as a material for an element used for phase control of an electromagnetic wave signal with a frequency of 1 MHz to 400 THz. A liquid crystal composition which contains at least one compound selected from the group consisting of compounds represented by Formula (1), and is used for phase control of an electromagnetic wave signal with a frequency of 1 MHz to 400 THz:

##STR00001##

Provided is a liquid crystal compound represented by formula I, ##STR00001##
the compound having a positive dielectric anisotropy, a great elastic constant and a good solubility. Further provided is a liquid crystal composition comprising the liquid crystal compound represented by formula I, the liquid crystal composition having a good stability against light and heat, a lower viscosity, a wider refractive index that may be achieved by the adjustment of the monomer ratio, and a higher clearing point (a very wide service temperature range), and in particular, the liquid crystal composition has a higher light transmittance, thus allowing a display device to have a higher brightness or an energy saving effect.

The present invention provides a liquid crystal composition, containing: one kind or two or more kinds of a first monomer having a first mesogenic skeleton, at least one polymerizable group represented by the general formula (PG1) linked to the first mesogenic skeleton, and at least one polar group linked to the mesogenic skeleton or the polymerizable group; and one kind or two or more kinds of a second monomer having a second mesogenic skeleton and a polymerizable group represented by the general formula (PG2) linked to the second mesogenic skeleton, and having a chemical structure different from that of the first monomer, in an amount of more than 0.4% by mass, which is excellent in vertical alignment, burn-in characteristics (change with time of pretilt angle), and compatibility, and provides a liquid crystal display element using the liquid crystal composition.

Disclosed is a liquid crystal display device comprising an array substrate and an opposite substrate arranged facing the array substrate, and further comprises a liquid crystal composition located between said array substrate and the opposite substrate, wherein said array substrate comprises elongated and evenly spaced slit electrodes and electrode gaps between the slit electrodes, with the slit electrodes and the electrode gaps said being located in the same layer structure; said array substrate comprises a bulk electrode below the slit electrodes; and said array substrate further comprises an insulating layer between the slit electrodes and the bulk electrode. The liquid crystal display device has a higher light transmittance, such that more backlight passes through the liquid crystal display device, resulting in the liquid crystal display device having a higher luminance.

The present invention is a liquid crystal display device including a liquid crystal layer containing a liquid crystal material, a sealing member surrounding the liquid crystal layer in a plan view, a pair of substrates sandwiching the liquid crystal layer, and an alignment control layer being in contact with the liquid crystal layer in a region surrounded by the sealing member in a plan view. The alignment control layer aligns a liquid crystal compound in the liquid crystal material in a direction horizontal to faces of the substrates, and contains a polymer formed by polymerization of at least one monomer, and the at least one monomer contains a monomer represented by the following Chemical formula (1):

##STR00001##

wherein at least one hydrogen atom of the phenylene group may be the same or different and may be substituted with a halogen atom, a methyl group, an ethyl group, or a propyl group.