Patent ID: 6372308
Filing Date: 2002-04-16
Classification: C09K

Abstract:
A liquid crystal composition comprising anti-ferroelectric liquid crystal compound (1) selected from liquid crystal compounds of the following formula (1) and a ferrielectric liquid crystal compound (2) or a racemic compound (2â€²) thereof, wherein the liquid crystal composition satisfies the following requirements (a) to (c),(a) the compositional ratio of the anti-ferroelectric liquid crystal compound (1) and the ferrielectric liquid crystal compound (2) or the racemic compound (2â€²) thereof is in the range of from a value which is on the anti-ferroelectric phase side and is apart from a value of a boundary compositional ratio by 5 mol % to a value which is on the ferrielectric phase side and is apart from the value of the boundary compositional ratio by 25 mol %, wherein the boundary compositional ratio is obtained on the basis of a liquid crystal phase diagram prepared on the basis of conoscopic image observations obtained by changing the mixing ratio of the anti-ferroelectric liquid crystal compound (1) and the ferrielectric liquid crystal compound (2) or the racemic compound (2â€²) thereof, (b) in an optical response to an applied voltage, the liquid crystal composition exhibits an optical response which is symmetrical in a positive voltage region and a negative voltage region and an hysteresis, in terms of a voltage difference, of 15% or less, on a saturated voltage value, and (c) the alignment stability of the liquid crystal composition is such that when measured for an optical response by applying a triangular voltage of +10V and 50 mHz at room temperature, in a test cell having upper and lower surfaces with electrodes formed thereon, but not connected, the maximum value of optical transmission thereof being defined to be 100%, the minimum value of the optical transmission by the measurement is taken as Ti (%), and, when measured for an optical response under the same conditions after the test cell is allowed to stand for 1 hour in a state where said electrodes formed on the upper and lower surfaces of the test cell are connected, the minimum value of the optical transmission is taken as Te (%), then (Teâˆ’Ti) value is 0.4% or less, â€ƒwherein R1 is a linear alkyl group having 8 to 11 carbon atoms, X1 is a hydrogen atom or a fluorine atom, A is â€”CH3 or â€”CF3, m is an integer of 1 or 3, n is an integer of 1 or 2, and C* is an asymmetric carbon atom.