Abstract: A liquid crystal device is constituted by a pair of substrates each provided with an electrode, and a chiral smectic liquid crystal composition disposed between the substrates. At least one of the substrates is provided with an alignment control film of a polyimide represented by the following formula (I): ##STR1## in which A denotes a planar tetravalent organic residue group; B denotes a divalent group represented by --CR.sub.1 (R.sub.2)-- where R.sub.1 and R.sub.2 independently denote H or alkyl group; a, b and c are independently 0 or 1; x and y are independently an integer of at least 0 and x+y=at least 1; and n is an integer of at least 2.

Abstract: A liquid crystal device is constituted by a chiral smectic liquid crystal and a pair of substrates sandwiching the chiral smectic liquid crystal therebetween and each having thereon an electrode for applying a voltage to the liquid crystal. At least one of the substrates being provided with an alignment control film comprising a specific aromatic polyimide which has been subjected to a uniaxial aligning treatment. The chiral smectic liquid crystal assumes bistability in a chiral smectic temperature range when incorporated in a test cell which is not provided with an alignment control film and has been subjected to shearing treatment. In the liquid crystal device including the polyimide alignment control film, the chiral smectic liquid crystal at least has a voltage-transmittance characteristic such that an effective tilt angle and a transmittance continuously change depending on an electric field applied thereto.

Abstract: A liquid crystal device is constituted by a pair of oppositely disposed substrates each provided with an alignment control layer, and a liquid crystal layer comprising a liquid crystal material and disposed between the substrates with a spacer member. In the device, the spacer member has an electrical conductivity larger than that of the liquid crystal material. Further, the liquid crystal layer containing the spacer member has a first resistance in a direction of a normal to the substrates in a prescribed temperature range substantially lower than a second resistance of a corresponding liquid crystal layer, in the identical direction, consisting only of the liquid crystal material and having the identical plane area and thickness. The liquid crystal device is effective in providing an improved drive margin in a wide temperature range while suppressing a DC offset voltage component applied to the liquid crystal layer.

Abstract: An aligning method of a chiral smectic liquid crystal includes the steps of: disposing a chiral smectic liquid crystal between a pair of electrode plates, the chiral smectic liquid crystal having a layer spacing-changing characteristic providing a layer spacing which increases on temperature decrease in a first temperature range in smectic A phase; and subjecting the chiral smectic liquid crystal to a heat treatment including a sequence of cooling from a higher temperature phase to a second temperature range in smectic A phase including at least a portion of the first temperature range, at least one cycle of heating and cooling within the second temperature range, and further cooling to a smectic phase lower than smectic phase. The heat treatment, particularly at least one cycle of heating and cooling in smectic A phase, is effective in suppressing an alignment (orientation) irregularity due to the presence of two regions different in characteristics, thus improving a drive margin.

Abstract: A liquid crystal apparatus comprises a liquid crystal device having a pair of substrates respectively having thereon scanning electrodes and data electrodes arranged in a matrix shape, and a liquid crystal disposed between the substrates and capable of a cumulative translational movement depending on a change in an external electric field applied to the liquid crystal; and a driver for controlling a first frequency f having a variable range and representing an effective frequency of a drive data signal pulse applied to the liquid crystal so that a second frequency f.sub.0 representing an inversion frequency at which a direction of the translational movement of the liquid crystal is turned in an opposite direction is in the variable range of the first frequency f. The above driver used in the liquid crystal apparatus is effective in suppressing a cumulative translational movement of liquid crystal molecules for a long period of time.

Abstract: A liquid crystal apparatus is constituted by a liquid crystal device including a pair of substrates and a liquid crystal disposed between the substrates, and means for applying an asymmetrical drive signal waveform to the liquid crystal. The liquid crystal is capable of having at least two stable states S1 and S2 and capable of causing a cumulative translational movement depending on a change in an external electric field applied to the liquid crystal. To the liquid crystal, an asymmetrical drive signal waveform having an effective frequency range is applied by the above application means so as to provide an absolute value of a difference between an inversion frequency f.sub.01 where a direction of the movement of said liquid crystal is turned in an opposite direction in the state S1 and an inversion frequency f.sub.

Abstract: A liquid crystal device is constituted by a pair of substrates each having thereon an electrode, and a smectic liquid crystal having a plurality of smectic liquid crystal layers disposed between the substrates. The smectic liquid crystal is disposed to form a first region wherein the smectic liquid crystal layers are aligned to have a layer inclination angle smaller than a calculated layer inclination angle based on a temperature-dependent layer spacing-changing characteristic or are aligned in a direction perpendicular to the substrates to form a bookshelf structure, and a second region wherein the smectic liquid crystal layers are aligned to form a chevron structure having a substantial layer inclination angle or having a layer inclination angle substantially equal to a calculated layer inclination angle based on a temperature-dependent layer spacing-changing characteristic.

Abstract: A liquid crystal device is constituted by a pair of transparent substrates each having thereon a transparent electrode, and a chiral smectic liquid crystal composition disposed between the substrates so as to assume at least two optically stable states. At least one of the substrates is provided with an alignment film which comprises a polyimide represented by a recurring unit of formula (I) shown below and has been subjected to a uniaxial aligning treatment. ##STR1## wherein A denotes a planar tetravalent organic residue group comprising an aromatic ring, an aromatic polycyclic ring, a heterocyclic ring or a condensed polycyclic ring, and B denotes a divalent aliphatic group comprising .paren open-st.CH.sub.2 .paren close-st..sub.n (n: an integer of at least 1) or an alicyclic ring.

Abstract: A liquid crystal device is constituted by a pair of substrates at least one of which is provided with an alignment control film, and a liquid crystal composition disposed between the substrates and contacting the alignment control film. The alignment control film comprises an amide polymer and a pyridine-based polymer. The liquid crystal device using a mixture alignment control film described above is effective in improving a switching characteristic by minimizing a depolarization field while keeping a uniform alignment characteristic.