The present invention provides a liquid crystal display device that includes a retardation layer with excellent thermal stability and suppresses a decrease in contrast ratio caused by scattering even when the retardation layer has been formed by polymerizing reactive monomers. The liquid crystal display device includes a pair of substrates and a liquid crystal layer held between the substrates. At least one of the substrates includes a retardation layer that contains a polymer of at least one type of monomer. The at least one type of monomer includes a photo-alignment monomer represented by a certain formula.

Shown is a liquid crystal display device including a first substrate, a second substrate and a liquid crystal composition having a nematic phase, which is placed between these substrates, wherein the liquid crystal composition includes at least one compound selected from compounds represented by formula (1) as a first component: ##STR00001##
wherein in formula (1), R.sup.1 and R.sup.2 are alkyl or the like; ring A and ring C are 1,4-phenylene or the like; ring B is 2,3-difluoro-1,4-phenylene or the like; Z.sup.1 and Z.sup.2 are a single bond or the like; and m is 1, 2 or 3, n is 0 or 1, and the sum of m and n is 3 or less.

Shown are a liquid crystal composition satisfying at least one of characteristics such as high maximum temperature, low minimum temperature, small viscosity, suitable optical anisotropy and large negative dielectric anisotropy, or the liquid crystal composition having a suitable balance regarding at least two of the characteristics; and an AM device including the composition. The liquid crystal composition contains a specific compound having small optical anisotropy as a first component, and a specific compound having large negative dielectric anisotropy as a second component, and may contain a specific compound having high maximum temperature or small viscosity as a third component, or a specific compound having a polymerizable group as an additive.

The invention relates to a liquid-crystalline medium which comprises at least one compound of the formula I, ##STR00001## in which R.sup.1, R.sup.1*, Z.sup.1, Z.sup.2 and L.sup.1-3 have the meanings defined herein, and to the use thereof for an active-matrix display, in particular based on the VA, PSA, PS-VA, PALC, FFS, PS-FFS, PS-IPS or IPS effect.

The present invention relates to polymerizable compounds, to processes and intermediates for the preparation thereof, to liquid-crystal media comprising them, and to the use of the polymerizable compounds and liquid crystalline media for optical, electro-optical and electronic purposes, in particular in liquid crystalline displays, especially in liquid crystalline displays of the polymer sustained alignment type.

To show a liquid crystal composition containing a polymerizable compound, to exhibit excellent persistence characteristics and display unevenness characteristics, a liquid crystal display device including such a composition, and an optical device. To show a liquid crystal composition containing the polymerizable compound and satisfying at least one of characteristics such as high maximum temperature, low minimum temperature, small viscosity, suitable optical anisotropy, large negative dielectric anisotropy and large specific resistance; and an AM device having characteristics such as a small persistence ratio, a short response time, a low threshold voltage, a large voltage holding ratio, a large contrast ratio and a long service life. The liquid crystal composition contains as a first component a polymerizable monomer that has a capability of a hydrogen bond donor and can form a hydrogen bond with an alignment film surface, or an oligomer, a prepolymer or a polymer of the monomer.

Liquid-crystalline media (LC media) comprising self-aligning mesogens (self-alignment additives) which effect homeotropic (vertical) alignment of the LC media at a surface or the cell walls of a liquid-crystal display (LC display). The self-alignment additives contain five-ring systems. LC displays having homeotropic alignment of the liquid-crystalline medium (LC medium) without conventional alignment layers are provided.

Liquid crystal displays having quick response and high light resistance are provided. A liquid crystal composition includes: (A) a cyclohexane compound of formula [I]:

##STR00001## wherein R and R are each independently a C.sub.1-C.sub.6 linear alkyl group; (B) a compound that is different from cyclohexane compound (A) and is a liquid crystal; and (C) at least one polymerizable compound selected from the group consisting of
a polymerizable compound of formula [II]:

P.sup.1-Sp.sup.1-E-Sp.sup.2-P.sup.2[II] wherein, e.g., P.sup.1 and P.sup.2 are each an acryloyloxy group, Sp.sup.1 and Sp.sup.2 are each an alkyleneoxy group or a direct bond, and E is an arylene group, and
a polymerizable compound of formula [III]:

A-(L-W).sub.i-(M-Z).sub.j(N).sub.kB[III] wherein, e.g., A and B are each P-Q-, P is a polymerizable group, Q is a spacer group or a single bond, i quantity of L and k quantity of N are each phenylene, j quantity of M are each phenylene, i quantity of W and j quantity of Z are each O, i and k are 0 or 1 with the proviso that i+k>0, j is 0, 1, 2 or 3, and n is 1, 2, 3 or 4; and optionally includes: (D) a photopolymerization initiator.

Provided are a liquid crystal device, a composition capable of forming a liquid crystal layer, a method of manufacturing the liquid crystal device, a system for manufacturing the liquid crystal device, and a use of the liquid crystal device. The liquid crystal device is a device capable of exhibiting, for example, a normally white or black mode, exhibiting a high contrast ratio, driven with a low driving voltage, and exhibiting excellent durability such as thermal stability. Such a liquid crystal device may be applied to various optical modulators such as a smart window, a window protective film, a flexible display device, an active retarder for displaying 3D images, or a viewing angle control film.

A polymerizable compound-containing liquid crystal composition of the present invention relates to a liquid crystal composition containing a polymerizable compound represented by general formula (I) and a compound represented by general formula (II) and can be used for a liquid crystal display device imparted with liquid crystal aligning ability by polymerization. The polymerizable liquid crystal composition is required to cause no precipitation in a wide temperature range and have a low viscosity corresponding to fast switching, and a liquid crystal display device using the composition is required to have more stable alignment after polymerization and to cause no defect in display characteristics. In the present invention, the problems can be solved using a specified compound.