Dielectrically positive liquid-crystalline media comprising a compound of the formula TINUVIN 770 and optionally one or more compounds of formula I, ##STR00001##
in which the parameters have the respective meanings indicated in the specification, and optionally one or more further dielectrically positive compounds and optionally one or more further dielectrically neutral compounds, and to liquid-crystal displays, especially active-matrix displays and in particular TN, IPS and FFS displays, containing these media.

The present invention relates to liquid-crystal (LC) media as defined in claim 1, having negative dielectric anisotropy and to the use thereof for optical, electro-optical and electronic purposes, in particular in LC displays.

A liquid crystal (LC) medium comprising a polymerizable compound, a process for its preparation, its use for optical, electro-optical and electronic purposes, such as LC displays, including LC displays of the polymer sustained alignment (PSA) type, and LC displays, including PSA displays, comprising the LC medium.

An object of the present invention is to provide a method for producing a reflective layer having an excellent diffuse reflectivity and a wide reflection wavelength range. Another object of the present invention is to provide a reflective layer having an excellent diffuse reflectivity and a wide reflection wavelength range. The method for producing a reflective layer of the present invention includes: a step 1 of applying a composition selected from the group consisting of the following composition X and the following composition Y onto a substrate to form a composition layer; a step 2 of heating the composition layer to align a liquid crystal compound in the composition layer into a cholesteric liquid crystalline phase state; a step 3 of cooling or heating the composition layer in a cholesteric liquid crystalline phase state to reduce a helical pitch; and a step 4 of irradiating at least a partial region of the composition layer with light, between the step 1 and the step 2, between the step 2 and the step 3, or after the step 3, to photosensitize a chiral agent A or a chiral agent C in the composition layer. Composition X: a composition including a liquid crystal compound, a chiral agent A whose helical twisting power is changed upon light irradiation, and a chiral agent B whose helical twisting power is increased upon cooling or heating. Composition Y: a composition including a liquid crystal compound and a chiral agent C whose helical twisting power is changed upon light irradiation and whose helical twisting power is increased upon cooling or heating.

Liquid crystal-based devices for detecting a target contaminant in air, including hydrogen, nitrogen dioxide, ozone, ammonia or carbon monoxide, and methods of using such devices to detect the target contaminant are disclosed. Such devices have a substrate surface that includes one or more metals or metal alloys that is in contact with a liquid crystal composition. When the device is contacted with a sample that contains the target contaminant, an observed change in the orientational ordering of the liquid crystal signals the presence of the target contaminant. In the absence of the target contaminant, no change in orientational ordering occurs.

A polymer having excellent liquid crystal alignment and electrical properties and thus is suitable for use as a liquid crystal alignment agent, a liquid crystal alignment agent including the same, a liquid crystal alignment film formed from the liquid crystal alignment agent, and a liquid crystal display device including the liquid crystal alignment film are provided.

The invention relates to a liquid-crystalline medium based on a mixture of polar compounds having positive dielectric anisotropy, characterised in that it comprises one or more compounds of the formula I in a total concentration of ≥40%, ##STR00001##
in which the parameters have the meanings indicated in claim 1, and to the use of the liquid-crystalline medium for electro-optical purposes, in particular in liquid-crystal light valves for lighting devices for motor vehicles, and to liquid-crystal light valves which comprise this medium and lighting devices for motor vehicles which contain such liquid-crystal light valves.

The present application relates to a novel liquid crystal compound and a use thereof. The novel liquid crystal compounds of the present application can exhibit a smectic A phase over a wide temperature range. The novel liquid crystal compounds of the present application can be usefully used in the technical fields to which smectic A liquid crystals can be applied, for example, bistable devices.

The present invention provides an optical film exhibiting high alignment and good phase difference development in an oblique direction, and a polarizing plate and an image display device using the same. This optical film of the present invention has a substrate; and a phase difference layer which is provided on the substrate to be adjacent to the substrate, in which the phase difference layer is a layer formed by fixing vertical alignment of a liquid crystal compound having a polymerizable group included in a liquid crystal composition containing the liquid crystal compound and a polymer compound, a difference in a value between the polymer compound and the substrate, which is calculated using three-dimensional SP values, is 3 or less, and a content of the polymer compound is less than 10 parts by mass with respect to 100 parts by mass of the liquid crystal compound.

The invention relates to a liquid-crystalline medium, preferably having a nematic phase and dielectric anisotropy of 0.5 or more, which comprises one or more compounds of formula Y ##STR00001##
in which the parameters have the meanings 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 Y for the improvement of the transmission and/or response times of a liquid-crystalline medium which comprises one or more additional mesogenic compounds.