The present invention relates to a liquid crystal (LC) medium comprising a compound of formula I

##STR00001## and one or more compounds selected from the group of compounds of the formulae IIA, IIB, IIC and IID,

##STR00002## as defined in claim 1, and to the use thereof for optical, electro-optical and electronic purposes, in particular in LC displays, especially in IPS, FFS, VA or PS-VA displays.

An optical device (20) includes an electro-optical layer, including a liquid crystal material (24) with a heliconical structure having a pitch that is less than 250 nm and is modifiable by an electric field. An array of excitation electrodes (28) extends over the electro-optical layer. Control circuitry (23) is coupled to apply control voltage waveforms to the excitation electrodes and is configured to modify the control voltage waveforms so as to locally modify a molecule director angle of the heliconical structure and thus to generate a specified phase modulation profile in the electro-optical layer.

A pressure-sensitive adhesive and a liquid crystal cell including the same are disclosed herein. In some embodiments, a pressure-sensitive adhesive having a storage elastic modulus of 700 kPa or more at a temperature of 25° C. and a frequency of 6 rad/sec, and a gel fraction of 35% or more, wherein the gel fraction is defined by Equation 1:

B/A×100  [Equation 1]

wherein, A is an initial mass (g) of the pressure-sensitive adhesive, B is a mass (g) of an insoluble content after the pressure-sensitive adhesive is immersed in a solvent at 60° C. for 24 hours and then dried at 150° C. for 30 minutes. The press-sensitive adhesive is advantageous for implementation into a flexible element between upper and lower substrates of a liquid crystal cell, and providing excellent electro-optical properties and appearance uniformity by minimizing defects.

A device includes a polymer stabilized blue phase liquid crystal (“PS-BPLC”) layer. The device also includes an alignment structure coupled with the PS-BPLC layer. LC molecules disposed in contact with the alignment structure are configured to have a spatially varying in-plane orientation pattern that is at least partially defined by the alignment structure. The PS-BPLC layer is configured to forwardly deflect a polarized light having a predetermined handedness, and transmit a polarized light having a handedness that is orthogonal to the predetermined handedness.

An optical film includes a plurality of helically arranged liquid crystals and organic solid crystal structures at least partially surrounding the plurality of helically arranged liquid crystals. A method of making the optical film includes obtaining a substrate with an alignment layer and a film of a first solution on the alignment layer. The first solution includes liquid crystals and organic crystal molecules. The liquid crystals form a plurality of helically arranged liquid crystals on the alignment layer. The method also includes forming organic solid crystal structures by crystallizing the organic crystal molecules. The organic solid crystal structures at least partially surround the plurality of helically arranged liquid crystals.

A device includes a polymer stabilized blue phase liquid crystal (“PS-BPLC”) layer. The device also includes an alignment structure coupled with the PS-BPLC layer. LC molecules disposed in contact with the alignment structure are configured to have a spatially varying in-plane orientation pattern that is at least partially defined by the alignment structure. The PS-BPLC layer is configured to forwardly deflect a polarized light having a predetermined handedness, and transmit a polarized light having a handedness that is orthogonal to the predetermined handedness.

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.

The disclosure discusses chiral dopants for liquid-crystalline materials. Chiral dopants can be bioreachable compounds, i.e. compounds produced from microbes through fermentation. Chiral dopants can also include bioreachable materials that are further modified by chemical synthetic steps. Chiral dopants as discussed herein can include biomolecules such as glycyrrhetinic acid (1), S-naringenin (2), shikimic acid (3), alpha-phellandrene (4), betulin (5), malic acid (6), valencene (7), or nootkatone (8), and any stereoisomers or chemically modified derivatives thereof. The disclosure further shows optical properties of such compounds in a liquid-crystalline material.

A liquid-crystalline medium which comprises at least one compound selected from the group of compounds of the formulae IA to IH,

##STR00001##

in which Z.sup.1 denotes a single bond, —CH.sub.2CH.sub.2—, —CH═CH—, —CH.sub.2O—, —OCH.sub.2—, —CF.sub.2O—, —OCF.sub.2—, —COO—, —OCO—, —C.sub.2F.sub.4—, —(CH.sub.2).sub.4—, —CHFCHF—, —CF.sub.2CH.sub.2—, —CH.sub.2CF.sub.2—, —C≡C—, —CF═CF—, —CH═CHCHO— or —CH.sub.2CF.sub.2O—,
and the use thereof for an active-matrix display, in particular based on the VA, PSA, PS-VA, PALC, FFS, PS-FFS, SA-VA, PS-IPS or IPS effect.

A lasing device includes an active layer comprising a cholesteric liquid crystal material and a laser dye, and a liquid crystal cell including spaced apart substrates defining a cell gap in which the active layer is disposed. The substrates include electrodes arranged to bias the active layer into an oblique helicoidal (Ch.sub.OH) state. At least one substrate of the liquid crystal cell is optically transparent for a lasing wavelength range of the device.