The present invention provides a novel liquid crystal material composition comprising one or more compound, in order to achieve the properties of low viscosity, high resistivity, good low-temperature mutual solubility, fast response, excellent transmission, and which can be used for a variety of fast response display modes. Since the working temperature of a LCD material is subjected to the temperature range of individual LC molecules, information can only be displayed in a specific temperature range of the specific liquid crystal macro-alignment phase. At low temperature, the viscosity of liquid crystal increases exponentially, which in turn substantially reduces the response speed and overall performances of the display system. The liquid crystal composition according to the present invention overcomes these problems with balanced chemical composition by achieving low viscosity, good low-temperature performance and excellent transmission in a wide range of LCD applications including TN, IPS or FFS displays, thus improving display performance.

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.

A liquid crystal compound comprising a specific compound having a positive dielectric anisotropy as the first component, and a specific compound having a low viscosity as a second component. Further, the liquid crystal compound may contain a specific compound having a positive dielectric anisotropy as the third component, a specific compound having a maximum temperature or a low viscosity as the fourth component, or a specific compound having a negative dielectric anisotropy as the fifth component.

A liquid crystal composition having one or more compounds represented by formula I, one or more compounds represented by formula II and one or more compounds represented by formula III: ##STR00001##
The liquid crystal composition has a good stability against light and heat and a lower viscosity, and can achieve a wider refractive index and higher clearing point by the adjustment the ratio of the monomers. In particular, the liquid crystal composition has a higher light transmittance, allowing a display device to have a higher brightness or an energy saving effect.

The present invention discloses an ultra-high-polarity chiral liquid crystal material, a liquid crystal laser and a preparation method therefor. The ultra-high-polarity chiral liquid crystal material has, in a certain temperature range, a high dielectric constant of 10.sup.4 and a characteristic of extremely-strong second harmonic response 3 to 10 times as much as that of a quartz crystal, and a pitch of the ultra-high-polarity chiral liquid crystal material is adjusted within 0.1 to 1 micrometer according to a doped concentration of the chiral molecule.

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, large negative dielectric anisotropy, large specific resistance, high stability to ultraviolet light and high stability to heat, or the liquid crystal composition having a suitable balance regarding at least two of the characteristics; and an AM device having characteristics such as a short response time, a large voltage holding ratio, low threshold voltage, a large contrast ratio and a long service life. The liquid crystal composition has negative dielectric anisotropy and contains a specific compound having large negative dielectric anisotropy as a first component, a specific compound having low minimum temperature as a second component, and a specific compound having small viscosity as a third component, and the composition may contain a specific compound having high maximum temperature or small viscosity as a fourth component, a specific compound having negative dielectric anisotropy as a fifth component, or a specific compound having a polymerizable group as an additive component.

A liquid crystal composition includes a polymerizable compound (or polymer) and a polar compound, where the homeotropic alignment of liquid crystal molecules can be achieved by the action of these compounds, and a liquid crystal display device includes such a composition. A nematic liquid crystal composition has positive dielectric anisotropy and includes a polymerizable compound as a first additive and a polar compound as a second additive, and the composition may include a specific liquid crystal compound having a large positive dielectric anisotropy and a specific liquid crystal compound having a high maximum temperature or a small viscosity, and a liquid crystal display device includes such a composition.

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, large dielectric anisotropy and a short helical pitch, or the liquid crystal composition 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 optically active compound as an additive, and a specific compound having high maximum temperature or small viscosity as a first component, and may contain a specific compound having positive dielectric anisotropy as a second component, or a specific compound having negative dielectric anisotropy as a third component.

The present invention provides a liquid crystal composition comprising: at least one compound of general Formula I; at least one compound of general Formula II; at least one compound of general Formula M and at least one compound of general Formula N. The present invention also provides a liquid crystal display device comprising the liquid crystal composition. The liquid crystal composition provided in the present invention has a higher optical anisotropy, a higher clearing point, a higher dielectric anisotropy, a high transmittance and a larger average elastic constant. When the liquid crystal composition is used in the IPS liquid crystal display device, the transmittance of the display device can be effectively improved, so that the display device has a good display performance while also having good energy-saving and environment-friendly characteristics.

##STR00001##

Provided are a liquid-crystal-medium having stability to heat, light and so forth, a wide liquid-crystal-phase temperature-range and significantly large dielectric-anisotropy and developing an optically isotropic liquid-crystal-phase; and various optical-devices used in a wide temperature-range, having short response-time, a large contrast-ratio and low drive-voltage and suppressing decrease in an effective dielectric-constant in a high-frequency range. A Liquid-crystal composition contains achiral-component T containing at least one compound selected from a first component represented by formula (1) and at least one compound selected from a second component represented by formula (2) or (3) and a chiral-agent to develop optically-isotropic liquid-crystal-phase: ##STR00001##
In formula (1), R.sup.1: alkyl, ring A.sup.1: 1,4-cyclohexylene, ring B.sup.1: 1,4-phenylene, L.sup.11 to L.sup.14: fluorine, Y.sup.1: fluorine, n.sup.1: 1 or 2, R.sup.2: alkyl, Z.sup.21 and Z.sup.22: single-bond or CF.sub.2O, L.sup.21 to L.sup.23: fluorine, Y.sup.2: fluorine, R.sup.3: alkyl, Z.sup.31 and Z.sup.32: single-bond or CF.sub.2O, L.sup.31 to L.sup.34: fluorine, Y.sup.3: fluorine, for example.