According to the present invention, there are provided a polarization filter and a sensor system. The polarization filter includes a circularly polarized light-separating layer having a cholesteric liquid crystalline phase fixed therein, in which the circularly polarized light-separating layer is a layer which selectively transmits one of the left-hand circularly polarized light and the right-hand circularly polarized light in the specific wavelength band, a /4 phase difference layer for light in the specific wavelength band is disposed on one of the surfaces of the circularly polarized light-separating layer, and the /4 phase difference layer includes a first phase difference region and a second phase difference region of which slow axis directions are orthogonal to each other. The sensor system includes the polarization filter, a light source which emits light having a wavelength in the specific wavelength band, and a light-receiving element which can detect light having a wavelength in the specific wavelength band. The polarization filter of the present invention can improve the sensitivity of a sensor system using polarized light, and the sensor system of the present invention has high sensitivity and is extremely cost effective.

A multilayer film and a preparation method thereof is provided, and belongs to the technical field of optical films. The provided multilayer film comprises an ultraviolet blocking material and a cholesteric liquid crystal layer. The cholesteric liquid crystal layer comprises a polymerizable liquid crystal monomer, a polymerizable chiral dopant and a photoinitiator. The multilayer film can filter ultraviolet rays and near infrared rays in natural light, thereby reducing the heat effect of the natural light and harms of the ultraviolet rays to people and objects. In addition, the multilayer film has a high visible light transmission rate, which does not distort the color of the natural light passing through.

The invention relates to a method of preparing a polymer film and to the use of such polymer film as in liquid crystal displays (LCDs) or other optical or electro optical devices, for decorative or security applications, as alignment layer or optical retardation film.

The invention relates to bimesogenic compounds of formula I ##STR00001##
wherein R.sup.11, R.sup.12, MG.sup.11, MG.sup.12, X.sup.11, X.sup.12 and Sp.sup.1 have the meaning given in claim 1, to the use of bimesogenic compounds of formula I in liquid crystal media and particular to flexoelectric liquid crystal devices comprising a liquid crystal medium according to the present invention.

The present invention relates to a composite material, a liquid crystal film, a method for preparing the film, a temperature-responsive device comprising the film, and a circular polarizer made therefrom. The liquid crystal film comprises the composite material of the present invention, wherein the composite material comprises a polymer network of a cholesteric liquid crystal material, and a chiral material capable of hydrogen-bond-assisted self-assembly, and wherein the chiral material is dispersed in and restrained by the polymer network. The obtained liquid crystal film can exhibit a high reflectivity and a high transmittance as well as a broad band reflection. And, the liquid crystal film is applicable for an industrial development because it can be produced with a simple process and at a lower cost, and requires a lower UV luminous intensity.

The present disclosure discloses a liquid crystal composition. The liquid crystal composition includes the following components in their respective mass percentages: 8%-50% of a polymerizable liquid crystal monomer; 1%-30% of a chiral reagent; 0.1%-5% of a photoinitiator; and 30%-70% of an organic solvent, wherein the liquid crystal composition after being cured exhibits visual angle dependent optical effect. In this way, the liquid crystal composition of the present disclosure includes no pigment particles or liquid crystal microcapsules, can be UV cured into film, and is applicable to being printed onto various substrates through gravure or flexo printing, so that it has a promising application prospect.

A liquid crystal medium has stability to heat, light and so forth, and significantly high dielectric anisotropy, and develops an optically isotropic liquid crystal phase. Moreover, various kinds of optical devices can be used in a wide temperature range and have a short response time, a large contrast ratio and low driving voltage. A liquid crystal composition contains achiral component T containing at least one compound 1 represented by formula (1) and a chiral agent, and develops the optically isotropic liquid crystal phase. ##STR00001## In formula (1), for examples, R.sup.1 is alkyl, L.sup.1 and L.sup.2 are each independently fluorine or hydrogen, and X.sup.1 is halogen.

The instant invention relates to mesogenic systems comprising a) a polymeric component, component A, obtained or obtainable from polymerisation of a precursor comprising one or more mesogenic mono-reactive compounds, one or more di-reactive compounds, which optionally are also mesogenic compounds and optionally a photo-initiator and a low molecular weight component, component B, comprising one or more mono-reactive, mesogenic compounds, one or more mesogenic compounds and one or more chiral dopants, exhibiting a Blue Phase, as well as to the use of these systems in deices and to these devices.

A blue phase liquid crystal composite material and a liquid crystal display comprising the same, can solve the problem of small Kerr constant of the current blue phase liquid crystal and the liquid crystal display comprising the same. The blue phase liquid crystal composite material of the present disclosure is produced by the photo polymerization of the components comprising: a parent blue phase liquid crystal, a benzyne compound, a chiral compound, a photo-polymerizable monomer, and a photoinitiator. The blue phase liquid crystal composite material of the present disclosure has the advantages of large Kerr constant, low voltage, high contrast, rapid response to electric field, good stability, and the like.

The present invention provides a liquid crystal composition, comprising one or more compounds shown as formula I and one or more compounds shown as formula II, and the liquid crystal composition comprising a compound shown as formula II-A:

##STR00001## wherein substituents are all defined.

The composition provided by the present invention has a low viscosity .sub.1, a moderate dielectric anisotropy and a moderate optical anisotropy n, and can achieve fast response of a liquid crystal display.