To provide a liquid crystal composition having at least one or a suitable balance regarding two of characteristics such as high maximum or low minimum temperature of a nematic phase, small viscosity, suitable optical anisotropy, large dielectric anisotropy, large specific resistance, high stability to ultraviolet light or heat and a large elastic constant; and an AM device including the composition and having a short response time, a large voltage holding ratio, low threshold voltage, a large contrast ratio, a long service life and so forth. The liquid crystal composition contains a quencher as an additive component and a specific compound having large positive dielectric anisotropy as a first component, and a liquid crystal display device includes the composition. The composition may contain a specific compound having high maximum temperature or small viscosity as a second component, or a specific compound having negative dielectric anisotropy as a third component.

There is provided a liquid crystal composition containing any one or two or more of compounds represented by general formula (i) below and any one or two or more of compounds represented by general formula (ii) below. ##STR00001##

The compounds of the formula I, and a liquid-crystalline medium, preferably having a nematic phase and negative dielectric anisotropy, which comprises a) one or more compounds of the formula I ##STR00001## and b) one or more compounds of the formulae II-1 to II-4, ##STR00002##
in which the parameters have the meanings defined herein, are suitable for use in an electro-optical display, particularly in an active-matrix display based on the VA, ECB, PALC, FFS or IPS effect.

The liquid crystal composition has the nematic phase and contains a specific compound having large positive dielectric anisotropy as a first component, and a specific compound having small viscosity as a second component, and may contain a specific compound having large positive dielectric anisotropy as a third component, a specific compound having a high maximum temperature or large positive dielectric anisotropy as a fourth component, or a specific compound having negative dielectric anisotropy as a fifth component, and a liquid crystal display device includes the composition.

Shown is a liquid crystal composition satisfying at least one of characteristics such as high maximum temperature, low minimum temperature, small viscosity, suitable optical anisotropy, large dielectric anisotropy and small frequency dependence, or has a suitable balance regarding at least two of the characteristics, and an AM device including the composition. The liquid crystal composition contains a specific compound having large positive dielectric anisotropy as a first component, and a specific compound having small viscosity as a second component, and may contain a specific compound having high maximum temperature or small viscosity as a third component, a specific compound having positive dielectric anisotropy as a fourth component or a specific compound having negative dielectric anisotropy as a fifth component.

A polymerizable compound-containing liquid crystal composition of the present invention relates to a liquid crystal composition containing a polymerizable compound represented by general formula (I) and a compound represented by general formula (II) and can be used for a liquid crystal display device imparted with liquid crystal aligning ability by polymerization. The polymerizable liquid crystal composition is required to cause no precipitation in a wide temperature range and have a low viscosity corresponding to fast switching, and a liquid crystal display device using the composition is required to have more stable alignment after polymerization and to cause no defect in display characteristics. In the present invention, the problems can be solved using a specified compound.

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

##STR00001## and b) one or more compounds selected from the group of compounds of the formulae II and III

##STR00002##

in which the parameters have the respective meanings indicated in claim 1, to the use thereof in an electro-optical display, particularly in an active-matrix display based on the VA, ECB, PALC, 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 I for reduction of the dispersion of the birefringence of a liquid-crystalline medium which comprises one or more compounds of the formulae II and/or III.

It is a method for manufacturing a liquid crystal display device in which an anchoring force causing liquid crystal molecules to be vertically aligned can be exerted sufficiently. A liquid crystal display device (1) including two substrates AM and CF and a liquid crystal layer (4) sandwiched therebetween can be manufactured. The liquid crystal display device manufacturing method includes: a first step of subjecting a surface of one of the substrates AM and CM that is to be in contact with the liquid crystal layer (4) to hydrophilization treatment; and a second step of disposing the two substrates AM and CF so as to face each other such that the two substrates are in contact with a liquid crystal composition containing liquid crystal molecules and an alignment aid having a polar group and having the function of causing the liquid crystal molecules to be aligned spontaneously.

It is a method for manufacturing a liquid crystal display device in which an anchoring force causing liquid crystal molecules to be vertically aligned can be exerted sufficiently. A liquid crystal display device (1) including two substrates AM and CF and a liquid crystal layer (4) sandwiched therebetween can be manufactured. The liquid crystal display device manufacturing method includes: a first step of subjecting a surface of one of the substrates AM and CM that is to be in contact with the liquid crystal layer (4) to hydrophilization treatment; and a second step of disposing the two substrates AM and CF so as to face each other such that the two substrates are in contact with a liquid crystal composition containing liquid crystal molecules and an alignment aid having a polar group and having the function of causing the liquid crystal molecules to be aligned spontaneously.

Provided are an alignment aid that sufficiently exerts an alignment control force causing liquid crystal molecules to be vertically aligned and can reduce a change in pretilt angle over time, a liquid crystal composition containing the alignment aid, and a liquid crystal display device. The alignment aid of the present invention has the function of causing the liquid crystal molecules to be aligned spontaneously. In the light absorption spectrum of the alignment aid, the longest wavelength at which the absorbance is 0.5 is 330 nm or shorter. Preferably, the light absorption spectrum is measured on a solution prepared by dissolving the alignment aid in tetrahydrofuran at a concentration of 1000 ppm.