An optical device includes a first electrode and a medium that includes ferroelectric liquid crystals and chiral dopants. The medium is located adjacent to the first electrode. The optical device may also include a second electrode distinct and separate from the first electrode. The optical device may be used as an optical dimming device, controlling an amount light passing through the optical device based on a voltage gradient provided to the optical device.

The new media exhibit a ferroelectric nematic phase preferably at ambient temperature. They preferably comprise one or more compounds selected from the group of compounds of formulae IA, IB and IC,

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in which the variable groups have the meanings indicated in the text and in the claims. Use of the media for providing ferroelectric nematic materials and a method of operation of an electro-optical device are presented. The media may be useful for energy-saving displays and electrical appliances.

New compounds and their mixtures enable the formation of the ferroelectric nematic liquid crystalline phase at ambient temperature. Compounds of the formula I are presented,

##STR00001## in which the variable groups have the meanings indicated in claim 1. Liquid crystal media comprise at least one compound of the formula I.

The present invention relates to a doped ferroelectric nematic liquid crystal having a chirality-induced stabilization of the polar nematic order, improved relaxation time for electro-optical switching, and selective reflection in the visible wavelength that is reversibly tunable. The ferroelectric nematic liquid crystal is doped with a chiral dopant selected from the group benzoic acid, 4-hexyl-,4-[[(1-methylheptyl)oxy]carbonyl]phenyl ester (ZLI811) and BDH1281.

A ferroelectric liquid crystal (FLC) material in a vertically aligned liquid crystal cell, comprising at least one chiral compound and at least one non-chiral liquid crystal compound, with a sub-micron scale helix pitch less than 300 nm, spontaneous polarization greater than 100 nC/cm2, and a tilt angle greater than 38 degrees. The ferroelectric liquid crystal (FLC) material provides an extremely large Kerr constant in a vertically aligned liquid crystal cell at the communication band of the light and therefore reduces the driving voltage and response time.

New classes of thiadiazole and oxadiazole compounds for use in LC mixtures are disclosed. In an embodiment, the new classes of thiadiazoles and oxadiazoles comprise at least one phenyl ring attached to the heterocyclic ring, where no alkyl, alkenyl or alkynyl tails are attached to the phenyl ring, but one alkyl, alkenyl or alkynyl tail is attached to the other end of the molecule, and a fluoro or cyano group appears in the para position of the phenyl ring. These compounds are disclosed as being effective at inducing smectic A phases in liquid crystal mixtures, particularly in liquid crystal mixtures also possessing a smectic C phase, more particularly in materials possessing a chiral smectic C (ferroelectric) phase.

A doped ferroelectric nematic liquid crystal includes a chirality-induced stabilization of the polar nematic order, improved relaxation time for electro-optical switching, and selective reflection in the visible wavelength that is reversibly tunable. The ferroelectric nematic liquid crystal is doped with a chiral dopant selected from benzoic acid, 4-hexyl-,4-[[(1-methylheptyl)oxy]carbonyl]phenyl ester (ZLI811) and BDH1281.

A modulator material layer includes a polymer matrix formed of a plurality of cross-linked polymer molecules and a plurality of droplets of liquid crystals within the polymer matrix. A planar macrocycle dye is dispersed within the plurality of droplets of liquid crystals. The planar macrocycle dye can include one or more of a phthalocanine, a porphyrin, a naphthalocyanine, a metallophthalocyanine, a metalloporphyrin, or a metallonaphthalocyanine.

A low birefringence ferroelectric liquid crystal (FLC) mixture composed of at least two components shows birefringence in the range 0.05 to 0.14, which is suitable for the modern display and photonic devices. The cell gap can be tuned from 1.5 m to 4 m to reduces the fabrication complexity and chromatic distortion by electro-optical modulation. The FLC mixtures can be employed in a wide temperature range. The characteristics of the said FLC mixture can be tuned by tuning the concentration of the constituents of the mixture. The helical pitch of the FLC mixtures can be varied from 100 nm to 10 m. A smectic tilt angle can be varied between 17 to 45 and the spontaneous polarization can be tuned over a wide range to meet requirements of different electro-optical modes, and the FLC mixture is applicable for a wide variety of electro-optical effects.

Material comprising a ferroelectric nematic phase, the material are disclosed. The material can include a mixture comprising first molecules and second molecules. At least one of a fluid of the first molecules and a fluid of the second molecules exhibits a ferroelectric nematic phase. The first molecules and second molecules are miscible. The first molecules can induce a polar orientational order of said second molecules.