Provided are a liquid crystal composition satisfying at least one of characteristics such as a high maximum temperature, a low minimum temperature, small viscosity, large optical anisotropy, large negative 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 may contain a specific compound having small viscosity or a low minimum temperature as a first component, a specific compound having large optical anisotropy and negative dielectric anisotropy as a second component, a specific compound having a high maximum temperature or small viscosity as a third component, a specific compound having negative dielectric anisotropy or a low minimum temperature as a fourth component, or a specific compound having a polymerizable group as an additive component.

The present invention relates to polymer stabilized nematic liquid crystal microlenses. The microlenses can be made from a nematic liquid crystal, a chiral dopant, a reactive monomer, and a photoinitiator. The microlenses can be prepared by spin coating a liquid crystal mixture onto an array including a nickel transmission electron microscope grid. The focal length of the microlens array can be tuned electrically.

There is provided a liquid crystal composition having the following properties without reductions in refractive index anisotropy (n) and nematic phase-isotropic liquid phase transition temperature (T.sub.ni): sufficiently small viscosity (), sufficiently small rotational viscosity (1), a large elastic constant (K.sub.33), and negative dielectric anisotropy () with a large absolute value. There is also provided a liquid crystal display device of, for example, a VA type in which such a liquid crystal composition is used and which has a high response speed and excellent display quality with defective display being eliminated or reduced. The liquid crystal display device using the liquid crystal composition of the present invention is useful as an active-matrix liquid crystal display device and can be used in liquid crystal display devices of, for instance, a VA mode and PSVA mode.

A nematic liquid crystal composition having negative dielectric anisotropy (), and a liquid crystal device element including the liquid crystal composition. The liquid crystal composition has sufficiently low viscosity (), sufficiently low rotational viscosity (1), a large elastic constant (K.sub.33), and a negative dielectric anisotropy () whose absolute value is large, without reducing the refractive index anisotropy (n) or the nematic-isotropic liquid phase transition temperature (T.sub.ni). A VA-mode liquid crystal display element including the liquid crystal composition, the liquid crystal display element having no or minimal display defects and having excellent display quality and a fast response. The liquid crystal display element including the liquid crystal composition is useful for an active matrix-addressed liquid crystal display element and used for, for example, a VA- or PSVA-mode liquid crystal display element.

The present invention provides a liquid crystal composition comprising one or more compounds of general formula I and one or more compounds of general formula II; the liquid crystal composition of the present invention can work at very high and very low temperatures, has a very short response time and a better reliability to light and heat, and particularly exhibits no image retention or a significantly reduced image retention after a long time operation.

To provide a liquid crystal compound satisfying at least one of physical properties such as high stability to light, a high clearing point, a low minimum temperature of a liquid crystal phase, small viscosity, suitable optical anisotropy, large dielectric anisotropy, a large dielectric constant in a minor axis direction, a suitable elastic constant and excellent compatibility; a liquid crystal composition containing the compound; and a liquid crystal display device including the composition. The compound is represented by formula (1): ##STR00001##

Disclosed are liquid crystal compounds of cycloalkyl-containing dibenzofuran derivatives, a preparation method therefor and use thereof. The compounds are as represented by formula I. In the molecular structures of the compounds of formula I provided by the present invention, liquid crystal compounds of cycloalkyl terminal group-containing dibenzofuran derivatives, compared with those having flexible alkyl chains as terminal groups, exhibit better intersolubility, and thus the use of a compound as represented by formula I provided by the present invention can improve the intersolubility of a liquid crystal compound and extend the application range of a liquid crystal mixture, producing an important application value.

##STR00001##

The invention relates to compounds of the formula I, to a liquid-crystalline medium which comprises at least one compound of the formula I, ##STR00001##
in which
R.sup.1, R.sup.1*, L.sup.1, L.sup.2, L.sup.3 and L.sup.4 have the meanings indicated herein,
and to the use thereof for an active-matrix display, in particular based on the VA, PSA, PS-VA, PM-VA, PALC, IPS, PS-IPS, SA-VA, SS-VA, FFS or PS-FFS effect.

Provided are a liquid crystal composition satisfying at least one of characteristics such as high maximum temperature, low minimum temperature, low viscosity, suitable optical anisotropy and large negative 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 specific compound having large negative dielectric anisotropy as a first component, and a specific compound having high maximum temperature or low viscosity as a second component, and may contain a specific compound having negative dielectric anisotropy as a third component, or a specific compound having a polymerizable group as an additive.

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.