A liquid crystal composition without requiring an alignment film or alignment treatment on a substrate. The problem is solved by a low molecular weight polar compound capable of homogeneously aligning a liquid crystal medium relative to the substrate, for example, a low molecular weight polar compound represented by formula (1).

M-P(1)

In formula (1), M is a nonpolar group having 1 or more carbons, and P is a polar group.

Disclosed is a liquid crystal composition comprising 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:

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The liquid crystal composition has simultaneously a lower rotary viscosity, a better photoelectric performance, a higher clearing point, a good low temperature performance, and less display defects. Further disclosed is a liquid crystal display element or device comprising the liquid crystal composition.

To show a liquid crystal composition containing a polymerizable compound, to exhibit excellent persistence characteristics and display unevenness characteristics, a liquid crystal display device including such a composition, and an optical device. To show a liquid crystal composition containing the polymerizable compound and satisfying at least one of characteristics such as high maximum temperature, low minimum temperature, small viscosity, suitable optical anisotropy, large negative dielectric anisotropy and large specific resistance; and an AM device having characteristics such as a small persistence ratio, a short response time, a low threshold voltage, a large voltage holding ratio, a large contrast ratio and a long service life. The liquid crystal composition contains as a first component a polymerizable monomer that has a capability of a hydrogen bond donor and can form a hydrogen bond with an alignment film surface, or an oligomer, a prepolymer or a polymer of the monomer.

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 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 compound having small optical anisotropy as a first component, and a specific compound having positive dielectric anisotropy 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.

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##

A negative dielectric anisotropy liquid crystal composition having one or more A-R.sub.0B compounds represented by formula I above as a first component, and one or more compounds represented by formula II above as a second component:

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The liquid crystal composition has a good stability against light and heat, a lower viscosity, a wider refractive index that may be achieved by adjusting the monomer ratio, and a higher clearing point (a very wide service temperature range). The liquid crystal composition has a higher light transmittance, thus allowing a display device to have a higher brightness or an energy saving effect.

Provided are a polymerizable compound represented by formula I and a liquid crystal composition comprising the polymerizable compound, particularly a PSVA liquid crystal composition for displays or TV applications and a PSA-IPS liquid crystal composition for an IPS mode; in particular, the polymerizable compound has a faster polymerization rate, and a material system formed from the selected polymerizable component and liquid crystal component has a lower rotary viscosity and better photoelectric properties, and has a high VHR after (UV) photoradiation, this avoiding the problem of the occurrence of residual images to final displays.

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Provided are a polymerizable compound represented by formula I and a liquid crystal composition formed by combining such a polymerizable compound with a specific liquid crystal component, particularly a PSVA liquid crystal composition for displays or TV applications and a PSA-IPS liquid crystal composition for an IPS mode; in particular, the polymerizable compound has a faster polymerization rate, and a material system formed from the selected polymerizable component and liquid crystal component has a low rotary viscosity and good photoelectric properties, and has a high VHR after (UV) photoradiation, this avoiding the problem of the occurrence of residual images to final displays.

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The liquid crystal material of the disclosure includes liquid crystal molecules, polymerizable monomers and a vertical alignment agent, wherein the polymerizable monomers and the vertical alignment agent can be polymerized under ultraviolet irradiation to form a polymer, while the polymer deposits on a substrate to form a polymer film capable of replacing the PI alignment film; so that an alignment process of the liquid crystal is simplified, and a cost is economized. The method of fabricating the liquid crystal display panel of the disclosure eliminates the fabricating process of the alignment film.

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