摘要:
Biphenyl esters of formula (I), wherein formula (II) represents formula (III) or formula (IV), R1 represents C3 - C12 alkyl, alkoxy, alkylcarbonyloxy, alkoxycarbonyl or alkoxycarbonyloxy, j is O or 1, R2 represents C3 - C12 alkyl or alkoxy, one of Q1 or Q2 is fluorine and the other is hydrogen, provided that when j is O and formula (II) is formula (III) and both R1 and R2 are n-alkyl, then the total number of carbon atoms in R1 and R2 is more than 12. These compounds may be used as constituents of liquid crystal mixtures which show a room temperature ferroelectric smectic phase, and a number of such mixtures are described.
摘要:
A method, device, and material for providing a fast switching liquid crystal display employs the ferro electric effect of chiral smectic liquid crystal material. To provide a uniform appearance the liquid crystal material is arranged to have a long cholesteric pitch at a temperature close to a smectic/cholesteric phase transition temperature. This long cholesteric pitch allows liquid crystal molecules to cool from the cholesteric to smectic phase with a uniform alignment. The smectic material is contained in a cell between walls (2, 3) bearing electrodes (5, 6) and surface treated to provide homogeneous alignment of liquid crystal material (7).
摘要:
A liquid crystal display (1, 20) is arranged to provide very low minimum light transmission in one of its two switchable states. This makes it useful for a shutter (Fig. 1) and for high contrast digital displays (Fig. 2). A layer (14) of a chiral smectic liquid crystal material is contained between two cell walls (9, 10) carrying electrode structures (11, 12). The liquid crystal material has the following phases with temperature: isotropic$(1,4)$cholesteric$(1,4)$chiral smectic$(1,4)$solid. The cholesteric pitch is large. The cell walls are surface treated to provide a parallel alignment of liquid crystal molecules. Crossed polarisers (2, 3) are arranged either side of the cell walls, one (2) aligned with its optical axis parallel to the surface alignment of the adjacent cell wall (9). The device is switched (5, 5) by means of +/- d.c. voltage pulses and utilises the ferro electric effect.
摘要:
Novel compounds suitable for inclusion in a ferroelectric smectic liquid crystal mixture, having formula (I), where the rings are independently phenyl, cyclohexyl or pyrimidyl, n is 0 or 1, m is 1, 2 or 3 (m + n is 1, 2 or 3), A, B, D, E are independently H or F, Z is a linking group or a single bond, R1 is alkyl or alkoxy, R2 is optically alkyl (n=0) or -COOR3 CH(CH3) COOR4 where R3 is optically active alkyl and R4 is n-alkyl (n=1), and a is 1 or 2. Ferroelectric smectic mixtures containing these compounds preferably in a non-optically active or racemic form aree described. Preferably each of the rings is phenyl.
摘要:
Optically active compounds of formula (I), where X has a structure (II) and B is C1-12 alkyl, a chiral group or a group having a general structure (III), where R and R' are H, C1-12 alkyl, alkoxy, alkylcarbonyloxy, or alkoxycarbonyl, each ring (IV) and (V) is the same or different, A and D are single bonds or bridging groups, each a and d is 0 or 1; Z, Z' are CN, Cl, F, Br or CF3; provided when Z is CN or Cl, then when B is alkyl X-Y is not (VI) or (VII). Ferroelectric smectic liquid crystal mixtures containing these compounds are also described.
摘要:
Novel amides of formula (I), where X is (II), and Y is (III), Z1, Z2 are -O- or NR°, R° being C1-12 alkyl or H, R1 is H, alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, halogen, cyano, R°COOCH(CH3)COO, R°OOCCH(CH3)OOC; A, B are -, OOC, COO, CH2CH2, -N=N-, -N(O)=N-; a, b, c, f, g, y are 0 or 1; R is CH3 or phenyl; D, E are H, alkyl, Y'-alkyl, Y''-alkoxy, or D and E together with the N represent the residue of an N-containing heterocyclic group; and (alpha) to (gamma) represent cyclic groups. Such compounds may be used in ferroelectric smectic liquid cystal mixtures, especially as pitch compensators. Preferred amides have y as O and X-CO-Z1-CH(R)- as formulae (IV) or (V). A liquid crystal composition and device using these amides are described.
摘要:
Esters de biphényle de formule (I) où formule (II) représente formule (III) ou formule (IV), R1 représente C3 - C12 alkyl, alkoxy, alkylcarbonyloxy, alkoxycarbonyl ou alkoxycarbonyloxy, j est égal à O ou 1, R2 représente C3 - C12 alkyl ou alkoxy, l'un de Q1 ou de Q2 est du fluor et l'autre de l'hydrogène, à condition que lorsque j = O et formule (II) représente formule (III) et que R1 et R2 sont n-alkyl, le nombre total d'atomes de carbone dans R1 et R2 soit supérieur à 12. Ces composés peuvent être utilisés comme constituants de mélanges à cristaux liquides présentant une phase smectique ferroélectrique à température ambiante. Un certain nombre de ces mélanges sont décrits.