Claims
- 1. A ferroelectric liquid crystal device having a pair of substrates each provided with voltage application means, an orientation control layer formed on at least one of the substrates, and a layer of ferroelectric liquid crystal composition formed between the pair of substrates, the device being characterized in that the ferroelectric liquid crystal composition comprises at least one compound (a) having an optically active group of the formula (I): ##STR128## and at least one compound (b) which is reverse to the compound (a) in the direction of a helical pitch induced in a nematic phase, the liquid crystal composition exhibiting at least a smectic C phase, smectic A phase and nematic phase at least 20 .mu.m in helical pitch,
- wherein the compound (a) is an optically active compound of the formula (II): ##STR129## wherein A.sub.1, A.sub.2 and A.sub.3 are each a 6-membered ring containing group selected from the group consisting of benzene, pyridine, pyrimidine, pyrazine, pyridazine, piperazine, cyclohexane, dioxacyclohexane, bicyclo octane and naphthalene ring, wherein one or more hydrogen atoms in the 6-membered ring-containing group may be substituted with a fluorine, chlorine or bromine atom, or cyano, nitro, methyl or methoxy group, X is --O--, --COO--, --OCO-- or a single bond, Y.sub.1 and Y.sub.2 are each --COO--, --OCO--, --OCH.sub.2 --, --CH.sub.2 O--, --CH.sub.2 CH.sub.2 --, --CH.dbd.CH--, --C.tbd.C-- or a single bond, R.sub.1 and R.sub.2 are a straight-chain or branched-chain alkyl having 1 to 15 carbon atoms, and n, p, q and r are each an integer of 0 to 1, and provided that formula II is not: ##STR130## and, wherein the compound (b) is a compound:
- (i) represented by formula (II) as defined above; or
- (ii) represented by one of the formulae: ##STR131## wherein R' and R" are the same of different and are each a straight-chain or branched-chain C.sub.1-15 alkyl alkoxy group, R"' is straight-chain or branched-chain C.sub.1-15 alkyl or alkoxy group or CH.sub.2 COOC.sub.2 H.sub.5, B is CH.sub.3, CN, CF.sub.3, CHF.sub.2", CH.sub.2 F or a halogen (Cl, F or Br), Y is --COO--, --OCO--, --OCH.sub.2 --, --CH.sub.2 O--, ##STR132## and n and m are each 0 or 1.
- 2. A device as defined in claim 1 wherein the group R.sub.2 --X--(A.sub.1 --Y.sub.1).sub.p --A.sub.2 Y.sub.2).sub.q --(A.sub.3).sub.r -- of the optically active compound of the formula (II) is represented by one formula selected from among the formulae: ##STR133## wherein R.sub.2 and p are as defined for the formula (II), n is 0 or 1, and Z' is --CN or F.
- 3. A device as defined in claim 1 or 2 wherein in the formula (II), R.sub.1 is a straight-chain or branched-chain C.sub.1-12 alkyl and R.sub.2 is a straight-chain or branched-chain C.sub.5-11 alkyl.
- 4. A ferroelectric liquid crystal device having a pair of substrates each provided with voltage application means, an orientation control layer formed on at least one of the substrates, and a layer of ferroelectric liquid crystal composition formed between the pair of substrates, the device being characterized in that the ferroelectric liquid crystal composition comprises at least one compound (a) having and optically active group of the formula (I): ##STR134## and at least one compound (b) which is reverse to the compound (a) in the direction of a helical pitch induced in a nematic phase, the liquid crystal composition exhibiting at least a smectic C phase, smectic A phase and nematic phase at least 20 .mu.m in helical pitch,
- wherein the compound (a) is an optically active compound of the formula (II'): ##STR135## wherein R.sub.9 is a straight-chain or branched -chain C.sub.1-15 aliphatic hydrocarbon group having or not having an intervening oxygen atom, R.sub.10 is a straight-chain or branched-chain C.sub.1-15 alkyl group, A.sub.4 is a phenylene group or cyclohexane group, and m and n are each 0 or 1,
- wherein R' and R" are the same of different and are each a straight-chain or branched-chain C.sub.1-15 alkyl alkoxy group, R"' is straight-chain or branched-chain C.sub.1-15 alkyl or alkoxy group or CH.sub.2 COOC.sub.2 H.sub.5, B is CH.sub.3, CN, CF.sub.3, CHF.sub.2", CH.sub.2 F or a halogen (Cl, F or Br), Y is --COO--, --OCO--, --OCH.sub.2 --, --CH.sub.2 O--,
- and n and m are each 0 or 1 and,
- wherein the compound (b) is a compound:
- (i) represented by formula (II') as defined above; or
- (ii) represented by one of the formulae: ##STR136## wherein R' and R" are the same of different and are each a straight-chain or branched-chain C.sub.1-15 alkyl alkoxy group, R"' is straight-chain or branched-chain C.sub.1-15 alkyl or alkoxy group or CH.sub.2 COOC.sub.2 H.sub.5, B is CH.sub.3, CN, CF.sub.3, CHF.sub.2", CH.sub.2 F or a halogen (Cl, F or Br), Y is --COO--,--OCO--,--OCH.sub.2,--CH.sub.2 O--,
- and n and m are each 0 or 1.
Priority Claims (1)
Number |
Date |
Country |
Kind |
1-62998 |
Mar 1989 |
JPX |
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Parent Case Info
This is a continuation of copending application(s) Ser. No. 07/493,145 filed on Mar. 13, 1990 now abandoned.
US Referenced Citations (7)
Foreign Referenced Citations (4)
Number |
Date |
Country |
88114609 |
Sep 1988 |
EPX |
63-30408 |
Dec 1988 |
JPX |
64-9286 |
Jan 1989 |
JPX |
2216540 |
Oct 1989 |
GBX |
Non-Patent Literature Citations (1)
Entry |
Yoshino, K. et al. IEEE Transactions 23 (4) 639, 1988. |
Continuations (1)
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Number |
Date |
Country |
Parent |
493145 |
Mar 1990 |
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