Liquid-crystalline media comprising one or more compounds of formula T ##STR00001##
as defined in claim 1, and high-frequency components comprising these media, especially microwave components for high-frequency devices, such as devices for shifting the phase of microwaves, tunable filters, tunable metamaterial structures, and electronic beam steering antennas, e.g. phased array antennas.

Provided is 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 and large dielectric anisotropy, or has 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 large negative dielectric anisotropy as a first component, a specific compound having a high maximum temperature or small viscosity as a second component, a specific compound having negative dielectric anisotropy as a third component, or a specific compound having a polymerizable group as an additive component.

Disclosed herein is a light emitting device and method of manufacturing such a device comprised of a series of photopolymerizable, chiral liquid crystalline layers that can be solvent cast on a substrate. The mixture of chiral materials in each successive layer may be blended in such a way that each layer has the same chiral pitch. Further the chiral materials in each layer may also be blended so that the ordinary and extraordinary refractive indices in each layer match the other layers such that the complete assembly of layers will optically function as a single relatively thick layer of chiral liquid crystal. The chiral nematic material in each layer can spontaneously adopt a helical structure with a helical pitch. The light emitting layers of the light emitting device can further comprise electroluminescent material that emits light into the band edge light propagation modes of the photonic crystal.

The invention relates to a liquid-crystalline medium having a nematic phase comprising one or more compounds of formula X

##STR00001##

wherein the parameters have the meaning given in the text, to the use thereof in an electro-optical display, particularly in an active-matrix display based on the 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 X for improvement of the transmission and/or response times of a liquid-crystalline medium which comprises one or more additional mesogenic compounds, as well as to the compounds of formula X.

An optical film of the present invention includes a positive A-plate and a positive C-plate, in which the Re(450), Re(550), and Re(650) of the positive A-plate satisfy the relationship of Re(450)≦Re(550)≦Re(650), the positive A-plate is formed of a cured product of a composition including the liquid crystal compound A, and the positive C-plate is formed of a cured product of a composition including the liquid crystal compound C.

Compounds of the formula I ##STR00001##
in which groups and parameters that occur have the definitions given in the disclosure. Preparation methods for these compounds. Uses of the compounds as components in liquid-crystalline media. Electrooptical display elements comprising the liquid-crystalline media.

An optical film includes a cholesteric liquid crystal layer formed in a stripe-shaped pattern in which an optically anisotropic region having optical anisotropy and an optically isotropic region having optical isotropy are alternately disposed, a helical axis of a cholesteric liquid crystal in the optically anisotropic region is oriented in one axial direction tin a plane of the optical film, and the helical axis is oriented in a normal direction t of a boundary surface between the optically anisotropic region and the optically isotropic region.

Reactive mesogens (RMs), mixtures and formulations comprising RMs, polymers obtained from such RMs and RM mixtures, and the use of the RMs, RM mixtures and polymers in optical or electrooptical components or devices, like optical films for liquid crystal displays (LCDs).

The present invention relates to a compound of the general formula I

##STR00001##

in which the occurring groups and parameters have the meanings indicated in claim 1, to the use thereof in liquid-crystalline or mesogenic media and to liquid-crystalline or mesogenic media comprising these derivatives.

Provided is an optically anisotropic layer having an excellent surface condition, with which an image display device having an excellent contrast can be manufactured; and an optical film, a polarizing plate, and an image display device, each having the optically anisotropic layer. The optically anisotropic layer is obtained by immobilizing a polymerizable liquid crystal composition including a polymerizable rod-shaped liquid crystal compound exhibiting a liquid crystal state of a smectic phase and an additive in a liquid crystal state of a smectic phase, in which a molecular length A (Å) of the polymerizable rod-shaped liquid crystal compound, a layer interval B (Å) of the smectic phase of the optically anisotropic layer, and a molecular length C (Å) of the additive satisfy a relationship of Expression (1-1), 0.5×B≤C≤0.6×A . . . (1-1).