A main object of the present invention is to provide a birefringence improving agent that can realize a satisfactory white display even in a liquid crystal display device in which a ferroelectric liquid crystal composition is used and which can reduce the birefringence and has a large cell gap; a ferroelectric liquid crystal composition and a liquid crystal display device that use the birefringence improving agent; and a compound that can be used in a ferroelectric liquid crystal composition.

Provided herein are ferroelectric nematic (N.sub.F) compositions comprising a ferroelectric nematic host and one or more nonlinear optical compounds (chromophores).

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, ##STR00001##
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.

The present invention discloses a ferroelectric helical liquid crystal material and a method for realizing second harmonic enhancement therefor. By means of the method, a ferroelectric helical liquid crystal with an ultrahigh polarity helical structure is obtained by doping chiral molecules with ferroelectric nematic phase liquid crystals, and a dielectric constant of the ferroelectric helical liquid crystal is 10.sup.4. This type of liquid crystal material has a superstrong nonlinear optical effect and can excite high-intensity second harmonic waves (for example, a nonlinear coefficient of the liquid crystal material is equivalent to that of a LiNbO.sub.3 nonlinear (NLO) crystalline material). Based on adjustability of a periodical helical structure of the ferroelectric helical liquid crystal, a molecular pitch of the ferroelectric helical liquid crystal is tuned by means of a concentration of chiral molecules (i.e., a polarization period is regulated).

Provided is a liquid crystal composition. The liquid crystal composition includes 1 to 50 wt % of an achiral smectic liquid crystal, and a remaining amount of a nematic liquid crystal. The nematic liquid crystal includes a negative nematic liquid crystal.

A liquid crystal panel comprises an array substrate and an opposing substrate that is opposite to the array substrate; a polymer dispersed blue phase layer configured to serve as an alignment layer is formed on the array substrate; and at least two electrodes are provided on the array substrate. The liquid crystal panel can omit a rubbing process for an alignment layer on a side of an array substrate, and resolve the problem of the dark-state light leakage of the liquid crystal panel. A method of manufacturing a liquid crystal panel is further disclosed.

Devices including nematic liquid crystal-forming molecules are disclosed. The molecules include one or more dipoles and exist in a ferroelectric nematic state. Exemplary devices can further include an electrode for applying an electric field in, for example, and in-plane direction.

Composite materials and devices including composite materials are disclosed. Exemplary composite materials include a porous material and ferroelectric nematic liquid crystal within pores of the porous material. The composite materials can be used in a variety of applications, such as capacitors, information storage and processing, actuators, sensors, electro-caloric devices, energy storage and/or conversion devices utilizing piezoelectric effects. The porous material can be a solid, a polymer, glassy, crystalline, amorphous, foam, an aerogel or ceramic.

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.

A polymer-stabilized liquid crystal (PSLC) composition includes a liquid crystal component having high dielectric constant, a chiral dopant, a stabilizing polymer, and a photo-initiator. Through the application of an applied voltage, the polymer-stabilized liquid crystal composition may be implemented to induce pixelated dimming in an AR display.