U.S. patent application number 09/826903 was filed with the patent office on 2002-05-09 for fluorine-substituted-4-alkenylbenzoic acid and derivatives thereof, and nematic liquid crystal composition containing cyanophenyl benzoate derivatives and liquid crystal display system using the same.
This patent application is currently assigned to DAINIPPON INK AND CHEMICALS, INC.. Invention is credited to Osawa, Masashi, Takatsu, Haruyoshi, Takehara, Sadao, Takeuchi, Kiyofumi.
Application Number | 20020053659 09/826903 |
Document ID | / |
Family ID | 26565530 |
Filed Date | 2002-05-09 |
United States Patent
Application |
20020053659 |
Kind Code |
A1 |
Takeuchi, Kiyofumi ; et
al. |
May 9, 2002 |
Fluorine-substituted-4-alkenylbenzoic acid and derivatives thereof,
and nematic liquid crystal composition containing cyanophenyl
benzoate derivatives and liquid crystal display system using the
same
Abstract
A novel liquid crystal compound, a nematic liquid crystal
composition, and a liquid crystal display system using the
composition are disclosed herein. The liquid crystal compound is
represented by the general formula (I): 1 wherein R represents a
hydrogen atom or a straight chain alkyl group having 1 to 7 carbon
atoms and each of X, Y and Z independently represents hydrogen atom
or fluorine atom. The nematic liquid crystal composition of the
present invention can provide liquid crystal materials in response
to desired purposes even by its addition in a small amount without
spoiling other characteristics.
Inventors: |
Takeuchi, Kiyofumi; (Tokyo,
JP) ; Takatsu, Haruyoshi; (Tokyo, JP) ;
Takehara, Sadao; (Chiba, JP) ; Osawa, Masashi;
(Saitama, JP) |
Correspondence
Address: |
ARMSTRONG,WESTERMAN, HATTORI,
MCLELAND & NAUGHTON, LLP
1725 K STREET, NW, SUITE 1000
WASHINGTON
DC
20006
US
|
Assignee: |
DAINIPPON INK AND CHEMICALS,
INC.
Tokyo
JP
|
Family ID: |
26565530 |
Appl. No.: |
09/826903 |
Filed: |
April 6, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
09826903 |
Apr 6, 2001 |
|
|
|
09200848 |
Nov 30, 1998 |
|
|
|
Current U.S.
Class: |
252/299.66 ;
252/299.01; 428/1.1 |
Current CPC
Class: |
C09K 2323/00 20200801;
C09K 19/46 20130101; C07C 63/04 20130101; Y10T 428/10 20150115;
C09K 19/2007 20130101 |
Class at
Publication: |
252/299.66 ;
428/1.1; 252/299.01 |
International
Class: |
C09K 019/52; C09K
019/12 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 28, 1997 |
JP |
P. HEI. 9-327904 |
Oct 29, 1998 |
JP |
P. HEI 10-308405 |
Claims
What is claimed is:
1. A compound, represented by the general formula (I): 362wherein R
represents a hydrogen atom or a straight chain alkyl group having 1
to 7 carbon atoms and each of X, Y and Z independently represents
hydrogen atom or fluorine atom.
2. The compound according to claim 1, wherein R is a hydrogen atom
or a methyl group.
3. The compound according to claim 1, wherein X is a fluorine atom
and Y is a hydrogen atom.
4. A compound, represented by the general formula (II): 363wherein
R represents a hydrogen atom or a straight chain alkyl group having
1 to 7 carbon atoms and Z represents a hydrogen atom or a fluorine
atom.
5. A nematic liquid crystal composition, comprising: a liquid
crystal component A composed of 1, 2 or 3 or more groups selected
from groups A1 to A6, wherein said groups are composed of compounds
represented by the general formulae (I-1) to (I-18):
20 Group A1 (I-1) 364 (I-2) 365 (I-3) 366 Group A2 (I-4) 367 (I-5)
368 (I-6) 369 Group A3 (I-7) 370 (I-8) 371 (I-9) 372 Group A4
(I-10) 373 (I-11) 374 (I-12) 375 Group A5 (I-13) 376 (I-14) 377
(I-15) 378 Group A6 (I-16) 379 (I-17) 380 (I-18) 381
wherein R.sup.11 each independently represents an alkyl or alkoxy
group having 1 to 10 carbon atoms and R.sup.12 each independently
represents an alkenyl or alkenyloxy group having 2 to 10 carbon
atoms, wherein said alkyl group, alkoxy group, alkenyl group or
alkenyloxy group may be unsubstituted or may have one F, CH.sub.3
or CF.sub.3 as a substituent group, and/or at least one of CH.sub.2
groups existing in said alkyl group, alkoxy group, alkenyl group or
alkenyloxy group may be substituted each independently with --O--,
--CO-- or --COO-- where O atoms are not directly linked to each
other, and the atoms which constitute these compounds may be
replaced by their isotopes, and said liquid crystal component A is
composed of 1 to 20 compounds; 0 to 95% by weight of a liquid
crystal component B composed of compounds having a dielectric
anisotropy of +2 or more; and 0 to 95% by weight of a liquid
crystal component C composed of compounds having a dielectric
anisotropy of from -10 or more to less than +2; wherein the total
amount of the liquid crystal component B and liquid crystal
component C in said nematic liquid crystal composition is from 30
to 90% by weight, with the proviso that the liquid crystal
component A should satisfy at least one of the following conditions
(i) to (viii): (i) said liquid crystal component A contains at
least one compound selected from the compounds represented by said
general formulae (I-11), (I-12), (I-14), (I-15), (I-17) and (I-18),
and the content of said compound in said liquid crystal component A
is from 5 to 100% by weight; (ii) said liquid crystal component A
contains 1 to 10 of the compounds represented by the group A5 and 1
to 10 of the compounds represented by the group A4 and/or group A6,
and the total content of these compounds in said liquid crystal
component A is from 5 to 100% by weight; (iii) said liquid crystal
component A contains 1 to 10 of the compounds represented by the
group A6 and 1 to 10 of the compounds represented by the group A4
and/or group A5, and the total content of these compounds in said
liquid crystal component A is from 5 to 100% by weight; (iv) said
liquid crystal component A contains 1 to 10 of the compounds
represented by the groups A4 to A6 in which the side chain group
has an alkenyl group and 1 to 10 of the compounds represented by
the groups A1 to A3 in which the side chain group has an alkyl
group, and the total content of these compounds in said liquid
crystal component A is from 5 to 100% by weight; (v) said liquid
crystal component A contains 1 to 10 of the compounds represented
by the group A3 and/or group A6 having 3,5-difluoro-4-cyanophenyl
group and 1 to 10 of the compounds represented by the group A2
and/or group A5 having 3-fluoro-4-cyanophenyl group, wherein at
least one of these selected compounds belongs to the group A5 or
group A6, and the total content of these compounds in said liquid
crystal component A is from 5 to 100% by weight; (vi) said liquid
crystal component A contains 1 to 10 of the compounds represented
by the group A3 and/or group A6 having 3,5-difluoro-4-cyanophenyl
group and 1 to 10 of the compounds represented by the group A1
and/or group A4 having 4-cyanophenyl group, wherein at least one of
these selected compounds belongs to the group A4 or group A6, and
the total content of these compounds in said liquid crystal
component A is from 5 to 100% by weight; (vii) said liquid crystal
component A contains 1 to 10 of the compounds represented by the
group A3 and/or group A6 having 3,5-difluoro-4-cyanophenyl group, 1
to 10 of the compounds represented by the group A2 and/or group A5
having 3-fluoro-4-cyanophenyl group and 1 to 10 of the compounds
represented by the group A1 and/or group A4 having 4-cyanophenyl
group, and the total content of these compounds in said liquid
crystal component A is from 5 to 100% by weight; and (viii) said
liquid crystal component A contains 1 to 10 of compounds in which
R.sup.12 is represented by CH.sub.2.dbd.CH--,
CH.sub.2.dbd.CH--(CH.sub.2)- .sub.2--,
CH.sub.2.dbd.CH--(CH.sub.2).sub.4--, CH.sub.3CH.dbd.CH--,
CH.sub.3CH.dbd.CH--(CH.sub.2).sub.2-- or
CH.sub.3CH.dbd.CH--(CH.sub.2).su- b.4--.
6. The nematic liquid crystal composition according to claim 5,
wherein said liquid crystal component B contains 1 to 15 compounds
selected from the group of compounds represented by the general
formulae (II-1) to (II-4): 382wherein each of R.sup.21 to R.sup.24
independently represents an alkyl group having 1 to 10 carbon atoms
or an alkenyl group having 2 to 10 carbon atoms, wherein said alkyl
group or alkenyl group may be unsubstituted or may have one F,
CH.sub.3 or CF.sub.3 as a substituent group, and/or at least one of
CH.sub.2 groups existing in said alkyl group or alkenyl group may
be substituted each independently with --O--, --CO-- or --COO--
where O atoms are not directly linked to each other, each of
X.sup.21 to X.sup.24 independently represents F, Cl, CF.sub.3,
OCF.sub.3, OCF.sub.2H, NCS or CN, each of Y.sup.21 to Y.sup.28
independently represents H, F, Cl or OCF.sub.3, each of W.sup.21 to
W.sup.28 independently represents H, F or Cl, each of Z.sup.21 to
Z.sup.26 independently represents a single bond, --COO--, --OCO--,
--CH.sub.2O--, --OCH.sub.2--, --(CH.sub.2).sub.2--,
--(CH.sub.2).sub.4--, --CH.dbd.CH--(CH.sub.2).sub.2--,
--(CH.sub.2).sub.2--CH.dbd.CH--, --CH.dbd.N--,
--CH.dbd.N--N.dbd.CH-- or --N(O).dbd.N--, wherein each of Z.sup.21
and Z.sup.24 to Z.sup.26 may be --CH.dbd.CH--, --CF.dbd.CF-- or
--C.ident.C--, each of the rings A.sup.21 to A.sup.24 independently
represents trans-1,4-cyclohexylene, trans-1,4-cyclohexenylene or
trans-1,3-dioxane-2,5-diyl, wherein the ring A.sup.24 may be
1,4-phenylene, 2- or 3-fluoro-1,4-phenylene or
3,5-difluoro-1,4-phenylene- , and in the case of
trans-1,4-cyclohexylene, at least one of the hydrogen atoms in said
ring may be replaced by deuterium atom, each of k.sup.21 to
k.sup.24 independently represents 0 or 1 wherein k.sup.3+k.sup.24
is 0 or 1, and the atoms which constitute the compounds of said
general formulae (II-1) to (II-4) may be replaced by their isotopic
atoms.
7. The nematic liquid crystal composition according to claim 6,
wherein said liquid crystal component B contains 1 to 15 or more
compounds selected from the group consisting of (1) a compound in
which each of R.sup.21 to R.sup.24 in the general formulae (II-1)
to (II-4) is independently an alkenyl group having 2 to 5 carbon
atoms, (2) a compound in which each of X.sup.21 to X.sup.24 in the
general formulae (II-1) to (II-4) is independently F, Cl, or
--OCF.sub.3, (3) a compound in which Z.sup.22 in the general
formula (II-1) is --(CH.sub.2).sub.2-- or --(CH.sub.2).sub.4--, (4)
a compound in which k.sup.21 in the general formula (II-1) is 1,
(5) a compound in which at least one of Y.sup.23, Y.sup.24,
W.sup.21 and W.sup.22 in the general formula (II-2) is F, (6) a
compound in which in the general formula (II-2) k.sup.22 is 1 and
Z.sup.24 is --C.ident.C--, (7) a compound in which in the general
formula (II-2) Z.sup.23 is a single bond or --(CH.sub.2).sub.2--
and Z.sup.24 is --COO--, (8) a compound in which at least one of
Y.sup.25, Y.sup.26 and W.sup.23 to W.sup.26 in the general formula
(II-3) is F, (9) a compound in which Z.sup.26 in the general
formula (II-3) is --C.ident.C--, (10) a compound in which in the
general formula (II-3) Z.sup.25 is a single bond or --C.ident.C--
and Z.sup.26 is --COO--, (11) a compound represented by the general
formula (II-4), and (12) a compound in which in the general
formulae (II-1) and (II-2) the rings A.sup.21 to A.sup.23 are
trans-1,4-cyclohexylene and at least one of the hydrogen atoms in
said ring is replaced by deuterium atom.
8. The nematic liquid crystal composition according to claim 6,
wherein said liquid crystal component B contains 1 to 15 compounds
selected from the group consisting of (1) a compound in which in
the general formula (II-1) R.sup.21 is an alkyl or alkenyl group
having 2 to 5 carbon atoms, k.sup.21 is 0 and X.sup.21 is --CN, (2)
a compound in which in the general formula (II-1) k.sup.21 is 1,
X.sup.21 is F or --CN and each of Y.sup.21 and Y.sup.22 is
independently H or F, (3) a compound in which in the general
formula (II-2) R.sup.22 is an alkyl or alkenyl group having 2 to 5
carbon atoms, k.sup.22 is 0, X.sup.22 is --CN and each of Y.sup.23,
Y.sup.24, W.sup.21 and W.sup.22 is independently H or F, (4) a
compound in which in the general formula (II-2) k.sup.22 is 1,
Z.sup.23 is a single bond, --(CH.sub.2).sub.2-- or --COO--,
Z.sup.24 is a single bond, --COO-- or --C.ident.C--, X.sup.22 is F
or --CN and each of Y.sup.23, Y.sup.24, W.sup.21 and W.sup.22 is
independently H or F, (5) a compound in which in the general
formula (II-3) R.sup.23 is an alkyl or alkenyl group having 2 to 5
carbon atoms and one of Z.sup.25 and Z.sup.26 is a single bond and
the other is a single bond, --COO-- or --C.ident.C--, (6) a
compound in which each of Y.sup.25, Y.sup.26 and W.sup.23 to
W.sup.26 in the general formula (II-3) is H or F, (7) a compound in
which in the general formula (II-4) R.sup.24 is an alkyl or alkenyl
group having 2 to 7 carbon atoms and k.sup.23+k.sup.24 is 0, and
(8) a compound in which in the general formulae (II-1) and (II-2)
the rings A.sup.21 to A.sup.23 are trans-1,4-cyclohexylene and at
least one of the hydrogen atoms in said ring is replaced by
deuterium atom; and wherein the total content of these compounds in
said liquid crystal component B is from 10 to 100% by weight.
9. The nematic liquid crystal composition according to claim 6,
wherein said liquid crystal component B contains 1 to 15 compounds
selected from the group consisting of (1) a compound in which in
the general formula (II-1) R.sup.21 is an alkyl or alkenyl group
having 2 to 5 carbon atoms, k.sup.21 is 1, one of Z.sup.21 and
Z.sup.22 is a single bond and the other is a single bond, --COO--,
--(CH.sub.2).sub.2-- or --(CH.sub.2).sub.4--, X.sup.21 is F, Cl,
CF.sub.3, OCF.sub.3 or OCF.sub.2H and at least one of Y.sup.21 and
Y.sup.22 is F, (2) a compound in which in the general formula
(II-2) R.sup.22 is an alkyl or alkenyl group having 2 to 5 carbon
atoms, k.sup.22 is 1, Z.sup.23 is a single bond,
--(CH.sub.2).sub.2-- or --COO--, Z.sup.24 is a single bond, --COO--
or --C.ident.C--, X.sup.22 is F, Cl, CF.sub.3, OCF.sub.3 or
OCF.sub.2H, at least one of Y.sup.23 and Y.sup.24 is F and each of
W.sup.21 and W.sup.22 is independently H or F, (3) a compound in
which in the general formula (II-3) R.sup.23 is an alkyl or alkenyl
group having 2 to 5 carbon atoms, one of Z.sup.25 and Z.sup.26 is a
single bond and the other is a single bond, --COO-- or
--C.ident.C--, X.sup.23 is F, at least one of Y.sup.25 and Y.sup.26
is F and W.sup.23 to W.sup.26 are H or one or more of them are F,
and (4) a compound in which in the general formulae (II-1) and
(II-2) the rings A.sup.21 to A.sup.23 are trans-1,4-cyclohexylene
and at least one of the hydrogen atoms in said ring is replaced by
deuterium atom; and wherein the total content of these compounds in
said liquid crystal component B is from 10 to 100% by weight.
10. The nematic liquid crystal composition according to claim 5,
wherein said liquid crystal component C contains 1 to 15 compounds
selected from the group consisting of compounds represented by the
general formulae (III-1) to (III-4): 383wherein each of R.sup.31 to
R.sup.38 independently represents an alkyl or alkoxy group having 1
to 7 carbon atoms or an alkenyl or alkenyloxy group having 2 to 7
carbon atoms, wherein said alkyl group, alkoxy group, alkenyl group
or alkenyloxy group may be unsubstituted or may have one F,
CH.sub.3 or CF.sub.3 as a substituent group, and/or at least one of
CH.sub.2 groups existing in said alkyl group, alkoxy group, alkenyl
group or alkenyloxy group may be substituted each independently
with --O--, --CO-- or --COO-- where O atoms are not directly linked
to each other, each of Y.sup.31 to Y.sup.36 independently
represents H or F, or Y.sup.33 and Y.sup.36 may also be --CH.sub.3,
each of W.sup.31 to W.sup.39 independently represents H, F or Cl,
each of Z.sup.31 to Z.sup.36 independently represents a single
bond, --COO--, --OCO--, --CH.sub.2O--, --OCH.sub.2--,
--(CH.sub.2).sub.2--, --(CH.sub.2).sub.4--,
--CH.dbd.CH--(CH.sub.2).sub.2--, --(CH.sub.2).sub.2--CH.dbd.CH--,
--CH.dbd.N--, --CH.dbd.N--N.dbd.CH-- or --N(O).dbd.N--, wherein
each of Z.sup.31 and Z.sup.34 to Z.sup.36 may also be
--CH.dbd.CH--, --CF.dbd.CF-- or --C.ident.C--, each of the rings
A.sup.31 to A.sup.35 independently represents
trans-1,4-cyclohexylene, trans-1,4-cyclohexenylene or
trans-1,3-dioxane-2,5-diyl, wherein each of the rings A.sup.31 and
A.sup.33 to A.sup.35 may also be 1,4-phenylene, 2- or
3-fluoro-1,4-phenylene, 2,3-difluoro-1,4-phenylene or
3,5-difluoro-1,4-phenylene and, in the case of
trans-1,4-cyclohexylene, at least one of the hydrogen atoms in said
ring may be replaced by deuterium atom, each of k.sup.31 to
k.sup.35 independently represents 0 or 1 wherein k.sup.34+k.sup.35
is 0 or 1, and the atoms which constitute the compounds of said
general formulae (III-1) to (III-4) may be replaced by their
isotopic atoms.
11. The nematic liquid crystal composition according to claim 10,
wherein said liquid crystal component C contains 1 to 15 compounds
selected from the group consisting of the compounds represented by
the general formula (III-1), (III-2) or (III-3), and the total
content of these compounds in said liquid crystal component C is
from 10 to 100% by weight.
12. The nematic liquid crystal composition according to claim 10,
wherein said liquid crystal component C contains 1 to 15 or more
compounds selected from the group consisting of (1) a compound in
which each of R.sup.31 to R.sup.34 in the general formulae (III-1)
to (III-4) is independently an alkenyl group having 2 to 5 carbon
atoms, (2) a compound in which each of R.sup.35 to R.sup.38 in the
general formulae (III-1) to (III-4) is independently a straight
chain alkenyl or alkenyloxy group having 2 to 7 carbon atoms, (3) a
compound in which in the general formula (III-1) k.sup.31 is 0 and
Z.sup.32 is a single bond or --(CH.sub.2).sub.2--, (4) a compound
in which k.sup.31 in the general formula (III-1) is 1, (5) a
compound represented by the general formula (III-2), (6) a compound
in which in the general formula (III-3) at least one of Y.sup.34,
Y.sup.35 and W.sup.34 to W.sup.36 is F and Y.sup.33 is F or
--CH.sub.3, (7) a compound in which in the general formula (III-3)
k.sup.33 is 0 and Z.sup.36 is a single bond, (8) a compound in
which in the general formula (III-3) k.sup.33 is 1 and Z.sup.35 is
a single bond, --OCO--, --CH.sub.2O--, --OCH.sub.2--,
--(CH.sub.2).sub.2--, --(CH.sub.2).sub.4--,
--CH.dbd.CH--(CH.sub.2).sub.2--, --(CH.sub.2).sub.2--CH.dbd.CH--,
--CH.dbd.N--, --CH.dbd.N--N.dbd.CH--, --N(O).dbd.N--, --CH.dbd.CH--
or --CF.dbd.CF--, (9) a compound in which in the general formula
(III-3) Z.sup.35 is --COO-- or --C.ident.C-- and Z.sup.36 is
--OCO--, --CH.sub.2O--, --OCH.sub.2--, --(CH.sub.2).sub.2--,
--(CH.sub.2).sub.4--, --CH.dbd.CH--(CH.sub.2).sub.2--,
--(CH.sub.2).sub.2--CH.dbd.CH--, --CH.dbd.N--,
--CH.dbd.N--N.dbd.CH--, --N(O).dbd.N--, --CH.dbd.CH--,
--CF.dbd.CF-- or --C.ident.C--, (10) a compound represented by the
general formula (III-4), and (11) a compound in which in the
general formulae (III-1) to (III-4) the rings A.sup.31 to A.sup.35
are trans-1,4-cyclohexylene and at least one of the hydrogen atoms
in said ring is replaced by deuterium atom.
13. The nematic liquid crystal composition according to claim 10,
wherein said liquid crystal component C contains 1 to 15 compounds
selected from the group consisting of (1) a compound in which in
the general formula (III-1) R.sup.31 is an alkyl group having 1 to
5 carbon atoms or an alkenyl group having 2 to 5 carbon atoms,
R.sup.35 is an alkyl or alkoxy group having 1 to 5 carbon atoms or
an alkenyl or alkenyloxy group having 2 to 5 carbon atoms, k.sup.31
is 0 and Z.sup.32 is a single bond, --COO-- or
--(CH.sub.2).sub.2--, (2) a compound in which in the general
formula (III-1) k.sup.31 is 1, the ring A.sup.31 is
trans-1,4-cyclohexylene and one of Z.sup.31 and Z.sup.32 is a
single bond and the other is --COO-- or --(CH.sub.2).sub.2--, (3) a
compound in which in the general formula (III-2) R.sup.32 is an
alkyl group having 1 to 5 carbon atoms or an alkenyl group having 2
to 5 carbon atoms, R.sup.36 is an alkyl or alkoxy group having 1 to
5 carbon atoms or an alkenyl or alkenyloxy group having 2 to 5
carbon atoms, the ring A.sup.32 is trans-1,4-cyclohexylene or
trans-1,4-cyclohexenylene, k.sup.32 is 0 and Z.sup.33 is a single
bond, --COO-- or --(CH.sub.2).sub.2--, (4) a compound in which in
the general formula (III-2) k.sup.32 is 1 and one of Z.sup.33 and
Z.sup.34 is a single bond, (5) a compound in which in the general
formula (III-3) R.sup.33 is an alkyl group having 1 to 5 carbon
atoms or an alkenyl group having 2 to 5 carbon atoms, R.sup.37 is
an alkyl or alkoxy group having 1 to 5 carbon atoms or an alkenyl
or alkenyloxy group having 2 to 5 carbon atoms, k.sup.33 is 0 and
Z.sup.36 is a single bond, --C.ident.C-- or --CH.dbd.N--N.dbd.CH--,
(6) a compound in which in the general formula (III-3) k.sup.33 is
1, Z.sup.35 is a single bond, --(CH.sub.2).sub.2--, --COO-- or
--C.ident.C-- and Z.sup.36 is a single bond, --COO-- or
--C.ident.C--, (7) a compound in which in the general formula
(III-3) one of Z.sup.35 and Z.sup.36 is a single bond and the other
is a single bond or --C.ident.C-- and at least one of W.sup.34 and
W.sup.35 is F, (8) a compound in which in the general formula
(III-3) either one of Y.sup.35 and Y.sup.36 is substituted with F
or CH.sub.3, and (9) a compound in which in the general formula
(III-4) R.sup.34 is an alkyl group having 1 to 5 carbon atoms or an
alkenyl group having 2 to 5 carbon atoms, R.sup.38 is an alkyl or
alkoxy group having 1 to 5 carbon atoms or an alkenyl or alkenyloxy
group having 2 to 5 carbon atoms and k.sup.34+k.sup.35 is 0, and
wherein the total content of these compounds in said liquid crystal
component C is from 10 to 100% by weight.
14. The nematic liquid crystal composition according to claim 5,
wherein said liquid crystal composition contains 1 to 10 compounds
having a core structure of four six-membered rings and having a
liquid crystal phase-isotropic liquid phase transition temperature
of 100.degree. C. or higher.
15. The nematic liquid crystal composition according to claim 5,
wherein said liquid crystal composition has a birefringence of from
0.08 to 0.195, an elastic constant ratio K.sub.33/K.sub.11 of from
1.1 to 4.0, a nematic phase-isotropic liquid phase transition
temperature of from 50 to 150.degree. C. and a crystal phase-,
smectic phase- or glass phase-nematic phase transition temperature
of from -200.degree. C. to 0.degree. C.
16. The nematic liquid crystal composition according to claim 5,
wherein said liquid crystal composition further contains a compound
having an optically active group which shows an induced helical
pitch of from 0.5 to 1,000 .mu.m.
17. An active matrix, twisted nematic or super twisted nematic
liquid crystal display system comprising the nematic liquid crystal
composition of claim 16.
Description
FIELD OF THE INVENTION
[0001] This invention relates to a fluorine-substituted
4-alkenylbenzoic acid and derivatives thereof, which are useful as
electro-optical display materials, and a nematic liquid crystal
composition containing cyanophenyl benzoate derivatives and a
liquid crystal display system using the same.
BACKGROUND OF THE INVENTION
[0002] TN-LCD (twisted nematic liquid crystal display device) is a
typical liquid crystal display device and used in clocks,
electronic calculators, electronic pocketbooks, pocket computers,
word processors, personal computers and the like. On the other
hand, with the increase in the information contents of OA
instruments, STN (super twisted nematic)-LCD has been developed by
Scheffer et al. (SID '85 Digest, p. 120, 1985) and Kinugawa et al.
(SID '86 Digest, p. 122, 1986) and is now popularizing in the field
of portable terminals, electronic pocketbooks, pocket computers,
word processors,-personal computers, monitor displays and the like
high information displays.
[0003] Recently, an active addressing drive system (Proc. 12th
IDRC, p. 503, 1992) and multiline addressing drive system (SID '92
Digest, p. 232, 1992) have been proposed for the purpose of
improving response characteristics of STN-LCD. Also, with the aim
of achieving brighter display or higher contrast ratio, a novel
reflection type liquid crystal color display system in which
birefringence of liquid crystal and retardation film was used in
stead of color filter layers (The Institute of Television Engineers
of Japan, Technical Reports, vol. 14, No. 10, p. 51, 1990) and a
liquid crystal display device having a refracting surface in which
a small parboloid is arranged on the substrate electrode side have
been proposed.
[0004] Particularly, uniform and high contrast display against the
temperature distribution of back light is expected for the purpose
of enlarging the display area, so that liquid crystal materials
having more stable orientation and smaller temperature-dependency
are expected, and a birefringence corresponding to a predetermined
value is also expected for reducing dispersion of cell thickness.
Since high duty drive is carried out by increasing the number of
pixels, response, gradient and the like are also regarded as
important factors. In the case of medium and small size portable
displays, on the other hand, stability of display against working
environmental temperature is an important point, so that liquid
crystal materials having lower driving voltage which can reduce
response and consumptive electric power are expected, as well as
smaller temperature dependency of driving voltage, sharpness and
frequency-dependency of desired duty drive within the temperature
range of from -30 to 0.degree. C. or from 40 to 80.degree. C. In
addition, though it is necessary to avoid too low electrical
resistance (specific resistance) for saving consumptive electric
power, it is required to set the resistance to a predetermined
value so that it does not become too high which will cause image
sticking. Thus, liquid crystal materials which are differentiated
further in detail and improved even to a certain degree are still
in demand.
[0005] As has been described in detail in the foregoing, there are
many demands for liquid crystal display devices, such as more
precise and high density display capacity, quicker response speed
(switching time) against driving voltage and environmental
temperature, lower driving voltage having chemically and
electrically high stability, higher gradient and higher contrast
for working environmental temperature and viewing angle. Because of
this, research and development are still carried out on liquid
crystal materials which can achieve desired driving voltage,
particularly lower driving voltage, with lower viscosity so that
the response property can be improved while having the nematic
property within a wide range of temperature and maintaining the
nematic phase for a prolonged period of time under low temperature
storage conditions. In addition, designing of birefringence,
dielectric anisotropy and elastic constant and their
temperature-dependency, light wave length-dependency of
birefringence and frequency-dependency of dielectric anisotropy in
response to duty numbers are also drawing attention as means to be
improved.
[0006] To meet such demands for liquid crystal materials, it is
necessary to generally optimize birefringence, elastic constant,
dielectric anisotropy, lower viscosity, wider nematic temperature
range, chemical stability, electric stability (desired specific
resistance) and the like physical characteristics and predetermined
tilt angle concerning orientation property, wider d/p margin and
the like individual characteristics, and the development of new
liquid crystal compounds or liquid crystal compositions is still in
demand.
[0007] With regard to the compounds related to the groups A1 to A3
of the present invention, which will be described in the following,
compounds of the general formula (I-1) are described for example in
German Patent 2306739 (1973) and J. Phys. (Paris), Suppl. 36, C1,
387 (1975), compounds of the general formula (I-4) are described in
JP-A-58-83665 (1983) (the term "JP-A" as used herein means an
"unexamined published Japanese patent application") and U.S. Pat.
No. 4,455,261 (1984) and compounds of the general formulae (I-2),
(I-3) and (I-5) to (I-9) are described in JP-W-3-503637 (the term
"JP-W" as used herein means an "unexamined published Japanese
international patent application") and WO 89/08102 (1989).
Compositions in which these compounds are used are described for
example in JP-A-9-157654 (1997) in addition to the just described
references.
[0008] With regard to compounds related to the groups A4 to A6 of
the present invention, which will be described in the following,
compounds of the general formulae (I-10) and (I-13) are described
in JP-A-2-225444 (1990), JP-A-2-233656 (1990), European Patent
464648 (1991), European Patent 466183 (1991) and JP-A-4-230352
(1992), and compounds of the general formula (I-16) are described
for example in JP-A-4-300861 (1992).
[0009] In addition to the aforementioned references, compositions
in which these compounds are used are described for example in
JP-W-62-501509 (1986), U.S. Pat. No. 4,818,426 (1989), European
Patent 207975 B (1990), JP-W-63-5025969 (1987), JP-W-1-500837
(1988), JP-A-4-279560 (1992), WO 96/32365 (1996), JP-A-9-59625
(1997), JP-A-9-227866 (1997), JP-A-10-88140 (1998), JP-A-10-140157
(1998) and JP-A-10-158651 (1998).
[0010] However, the aforementioned techniques, even some of them
are unrealized, are not sufficient for achieving objects of the
present invention. For example, compounds of the general formulae
(I-11) and (I-12) and compounds of the general formulae (I-14) and
(I-15) or the general formulae (I-17) and (I-18) of the present
invention are not known. With regard to techniques concerning the
compositions, descriptions about general combinations of compounds
can be found illustratively, but their illustrative examples are
rare, so that technical disclosures which can be used easily by
those skilled in the art are not sufficient yet.
[0011] In addition, even if the aforementioned techniques are used,
problems still remain unsettled. For example, great concern has
been directed toward the improvement of the response property of
liquid crystal display by smaller viscoelasticity in comparison
with the size of dielectric anisotropy .DELTA..epsilon. or the
realization of liquid crystal display which can be driven within a
wide range of temperature by obtaining a nematic phase that is
stable at a low temperature through the reduction of a
crystallizing or precipitating tendency against other liquid
crystal materials. Also, in the case of word processors, personal
computers and the like STN-LCDs having large information capacity,
small frequency dependency of driving voltage to cope with high
duty, or small temperature dependency of driving voltage in the
case of portable use, is expected. Because of this, more excellent
new liquid crystal materials are expected.
SUMMARY OF THE INVENTION
[0012] This invention contemplates overcoming the aforementioned
problems involved in the prior art.
[0013] Illustratively, its primary object is to provide a novel
liquid crystal compound which is strong polar compound having large
dielectric anisotropy and exerts excellent threshold voltage
reducing effect and excellent miscibility with conventional liquid
crystal materials by its addition.
[0014] Another object of the present invention is to provide liquid
crystal materials in response to each purpose without spoiling
other characteristics, including a case of its addition in a small
amount. More particularly, the object is to expand operating
temperature range of liquid crystal display characteristics through
the improvement of miscibility, low temperature shelf life and the
like, to improve reduction of driving voltage and its temperature
changes and to achieve or improve relatively quick response to a
desired driving voltage.
[0015] Still another object is to provide TN-LCD, STN-LCD and the
like liquid crystal display systems with improved electro-optical
characteristics making use of the liquid crystal compositions as
constituting materials.
[0016] The present invention have found the following items as
means for overcoming the aforementioned problems:
[0017] 1. a compound, represented by the general formula (I): 2
[0018] wherein R represents a hydrogen atom or a straight chain
alkyl group having 1 to 7 carbon atoms and each of X, Y and Z
independently represents hydrogen atom or fluorine atom.
[0019] 2. The compound described in the aforementioned item 1,
wherein R is a hydrogen atom or a methyl group.
[0020] 3. The compound described in the aforementioned item 1 or 2,
wherein X is a fluorine atom and Y is a hydrogen atom.
[0021] 4. A compound, represented by the general formula (II):
3
[0022] wherein R represents a hydrogen atom or a straight chain
alkyl group having 1 to 7 carbon atoms and Z represents a hydrogen
atom or a fluorine atom.
[0023] 5. A nematic liquid crystal composition, comprising:
[0024] a liquid crystal component A composed of 1, 2 or 3 or more
groups selected from groups A1 to A6, wherein said groups are
composed of compounds represented by the general formulae (I-1) to
(I-18): 4
[0025] wherein R.sup.11 each independently represents an alkyl or
alkoxy group having 1 to 10 carbon atoms and R.sup.12 each
independently represents an alkenyl or alkenyloxy group having 2 to
10 carbon atoms, wherein said alkyl group, alkoxy group, alkenyl
group or alkenyloxy group may be unsubstituted or may have one F,
CH.sub.3 or CF.sub.3 as a substituent group, and/or at least one of
CH.sub.2 groups existing in said alkyl group, alkoxy group, alkenyl
group or alkenyloxy group may be substituted each independently
with --O--, --CO-- or --COO-- where O atoms are not directly linked
to each other, and the atoms which constitute these compounds may
be replaced by their isotopes, and
[0026] said liquid crystal component A is composed of 1 to 20
compounds;
[0027] 0 to 95% by weight of a liquid crystal component B composed
of compounds having a dielectric anisotropy of +2 or more; and
[0028] 0 to 95% by weight of a liquid crystal component C composed
of compounds having a dielectric anisotropy of from -10 or more to
less than +2;
[0029] wherein the total amount of the liquid crystal component B
and liquid crystal component C in said nematic liquid crystal
composition is from 30 to 90% by weight, with the proviso that the
liquid crystal component A should satisfy at least one of the
following conditions (i) to (viii):
[0030] (i) said liquid crystal component A contains at least one
compound selected from the compounds represented by said general
formulae (I-11), (I-12), (I-14), (I-15), (I-17) and (I-18), and the
content of said compound in said liquid crystal component A is from
5 to 100% by weight;
[0031] (ii) said liquid crystal component A contains 1 to 10 of the
compounds represented by the group A5 and 1 to 10 of the compounds
represented by the group A4 and/or group A6, and the total content
of these compounds in said liquid crystal component A is from 5 to
100% by weight;
[0032] (iii) said liquid crystal component A contains 1 to 10 of
the compounds represented by the group A6 and 1 to 10 of the
compounds represented by the group A4 and/or group A5, and the
total content of these compounds in said liquid crystal component A
is from 5 to 100% by weight;
[0033] (iv) said liquid crystal component A contains 1 to 10 of the
compounds represented by the groups A4 to A6 in which the side
chain group has an alkenyl group and 1 to 10 of the compounds
represented by the groups A1 to A3 in which the side chain group
has an alkyl group, and the total content of these compounds in
said liquid crystal component A is from 5 to 100% by weight;
[0034] (v) said liquid crystal component A contains 1 to 10 of the
compounds represented by the group A3 and/or group A6 having
3,5-difluoro-4-cyanophenyl group and 1 to 10 of the compounds
represented by the group A2 and/or group A5 having
3-fluoro-4-cyanophenyl group, wherein at least one of these
selected compounds belongs to the group A5 or group A6, and the
total content of these compounds in said liquid crystal component A
is from 5 to 100% by weight;
[0035] (vi) said liquid crystal component A contains 1 to 10 of the
compounds represented by the group A3 and/or group A6 having
3,5-difluoro-4-cyanophenyl group and 1 to 10 of the compounds
represented by the group A1 and/or group A4 having 4-cyanophenyl
group, wherein at least one of these selected compounds belongs to
the group A4 or group A6, and the total content of these compounds
in said liquid crystal component A is from 5 to 100% by weight;
[0036] (vii) said liquid crystal component A contains 1 to 10 of
the compounds represented by the group A3 and/or group A6 having
3,5-difluoro-4-cyanophenyl group, 1 to 10 of the compounds
represented by the group A2 and/or group A5 having
3-fluoro-4-cyanophenyl group and 1 to 10 of the compounds
represented by the group A1 and/or group A4 having 4-cyanophenyl
group, and the total content of these compounds in said liquid
crystal component A is from 5 to 100% by weight; and
[0037] (viii) said liquid crystal component A contains 1 to 10 of
compounds in which R.sup.12 is represented by CH.sub.2.dbd.CH--,
CH.sub.2.dbd.CH--(CH.sub.2).sub.2--,
CH.sub.2.dbd.CH--(CH.sub.2).sub.4--, CH.sub.3CH.dbd.CH--,
CH.sub.3CH.dbd.CH--(CH.sub.2).sub.2-- or
CH.sub.3CH.dbd.CH--(CH.sub.2).sub.4--.
[0038] 6. The nematic liquid crystal composition described in the
aforementioned item 5, wherein said liquid crystal component B
contains 1 to 15 compounds selected from the group of compounds
represented by the general formulae (II-1) to (II-4): 5
[0039] wherein each of R.sup.21 to R.sup.24 independently
represents an alkyl group having 1 to 10 carbon atoms or an alkenyl
group having 2 to 10 carbon atoms, wherein said alkyl group or
alkenyl group may be unsubstituted or may have one F, CH.sub.3 or
CF.sub.3 as a substituent group, and/or at least one of CH.sub.2
groups existing in said alkyl group or alkenyl group may be
substituted each independently with --O--, --CO-- or --COO-- where
O atoms are not directly linked to each other, each of X.sup.21 to
X.sup.24 independently represents F, Cl, CF.sub.3, OCF.sub.3,
OCF.sub.2H, NCS or CN, each of Y.sup.21 to Y.sup.28 independently
represents H, F, Cl or OCF.sub.3, each of W.sup.21 to W.sup.28
independently represents H, F or Cl, each of Z.sup.21 to Z.sup.26
independently represents a single bond, --COO--, --OCO--,
--CH.sub.2O--, --OCH.sub.2--, --(CH.sub.2).sub.2--,
--(CH.sub.2).sub.4--, --CH.dbd.CH--(CH.sub.2).sub.2--,
--(CH.sub.2).sub.2--CH.dbd.CH--, --CH.dbd.N--,
--CH.dbd.N--N.dbd.CH-- or --N(O).dbd.N--, wherein each of Z.sup.21
and Z.sup.24 to Z.sup.26 may be --CH.dbd.CH--, --CF.dbd.CF-- or
--C.ident.C--, each of the rings A.sup.21 to A.sup.24 independently
represents trans-1,4-cyclohexylene, trans-1,4-cyclohexenylene or
trans-1,3-dioxane-2,5-diyl, wherein the ring A.sup.24 may be
1,4-phenylene, 2- or 3-fluoro-1,4-phenylene or
3,5-difluoro-1,4-phenylene- , and in the case of
trans-1,4-cyclohexylene, at least one of the hydrogen atoms in said
ring may be replaced by deuterium atom, each of k.sup.21 to
k.sup.24 independently represents 0 or 1 wherein k.sup.23+k.sup.24
is 0 or 1, and the atoms which constitute the compounds of said
general formulae (II-1) to (II-4) may be replaced by their isotopic
atoms.
[0040] 7. The nematic liquid crystal composition described in the
aforementioned item 6, wherein said liquid crystal component B
contains 1 to 15 or more compounds selected from the group
consisting of (1) a compound in which each of R.sup.21 to R.sup.24
in the general formulae (II-1) to (II-4) is independently an
alkenyl group having 2 to 5 carbon atoms, (2) a compound in which
each of X.sup.21 to X.sup.24 in the general formulae (II-1) to
(II-4) is independently F, Cl, or --OCF.sub.3, (3) a compound in
which Z.sup.22 in the general formula (II-1) is
--(CH.sub.2).sub.2-- or --(CH.sub.2).sub.4--, (4) a compound in
which k.sup.21 in the general formula (II-1) is 1, (5) a compound
in which at least one of Y.sup.23, Y.sup.24, W.sup.21 and W.sup.22
in the general formula (II-2) is F, (6) a compound in which in the
general formula (II-2) k.sup.22 is 1 and Z.sup.24 is --C.ident.C--,
(7) a compound in which in the general formula (II-2) Z.sup.23 is a
single bond or --(CH.sub.2).sub.2-- and Z.sup.24 is --COO--, (8) a
compound in which at least one of Y.sup.25, Y.sup.26 and W.sup.23
to W.sup.26 in the general formula (II-3) is F, (9) a compound in
which Z.sup.26 in the general formula (II-3) is --C.ident.C--, (10)
a compound in which in the general formula (II-3) Z.sup.25 is a
single bond or --C.ident.C-- and Z.sup.26 is --COO--, (11) a
compound represented by the general formula (II-4), and (12) a
compound in which in the general formulae (II-1) and (II-2) the
rings A.sup.21 to A.sup.23 are trans-1,4-cyclohexylene and at least
one of the hydrogen atoms in said ring is replaced by deuterium
atom.
[0041] 8. The nematic liquid crystal composition described in the
aforementioned item 6, wherein said liquid crystal component B
contains 1 to 15 compounds selected from the group consisting of
(1) a compound in which in the general formula (II-1) R.sup.21 is
an alkyl or alkenyl group having 2 to 5 carbon atoms, k.sup.21 is 0
and X.sup.21 is --CN, (2) a compound in which in the general
formula (II-1) k.sup.21 is 1, X.sup.21 is F or --CN and each of
Y.sup.21 and Y.sup.22 is independently H or F, (3) a compound in
which in the general formula (II-2) R.sup.22 is an alkyl or alkenyl
group having 2 to 5 carbon atoms, k.sup.22 is 0, X.sup.22 is --CN
and each of Y.sup.23, Y.sup.24, W.sup.21 and W.sup.22 is
independently H or F, (4) a compound in which in the general
formula (II-2) k.sup.22 is 1, Z.sup.23 is a single bond,
--(CH.sub.2).sub.2-- or --COO--, Z.sup.24 is a single bond, --COO--
or --C.ident.C--, X.sup.22 is F or --CN and each of Y.sup.23,
Y.sup.24, W.sup.21 and W.sup.22 is independently H or F, (5) a
compound in which in the general formula (II-3) R.sup.23 is an
alkyl or alkenyl group having 2 to 5 carbon atoms and one of
Z.sup.25 and Z.sup.26 is a single bond and the other is a single
bond, --COO-- or --C.ident.C--, (6) a compound in which each of
Y.sup.25, Y.sup.26 and W.sup.23 to W.sup.26 in the general formula
(II-3) is H or F, (7) a compound in which in the general formula
(II-4) R.sup.24 is an alkyl or alkenyl group having 2 to 7 carbon
atoms and k.sup.23+k.sup.24 is 0, and (8) a compound in which in
the general formulae (II-1) and (II-2) the rings A.sup.21 to
A.sup.23 are trans-1,4-cyclohexylene and at least one of the
hydrogen atoms in said ring is replaced by deuterium atom; and
[0042] wherein the total content of these compounds in said liquid
crystal component B is from 10 to 100% by weight.
[0043] 9. The nematic liquid crystal composition described in the
aforementioned item 6, wherein said liquid crystal component B
contains 1 to 15 compounds selected from the group consisting of
(1) a compound in which in the general formula (II-1) R.sup.21 is
an alkyl or alkenyl group having 2 to 5 carbon atoms, k.sup.21 is
1, one of Z.sup.21 and Z.sup.22 is a single bond and the other is a
single bond, --COO--, --(CH.sub.2).sub.2-- or --(CH.sub.2).sub.4--,
X.sup.21 is F, Cl, CF.sub.3, OCF.sub.3 or OCF.sub.2H and at least
one of Y.sup.21 and Y.sup.22 is F, (2) a compound in which in the
general formula (II-2) R.sup.22 is an alkyl or alkenyl group having
2 to 5 carbon atoms, k.sup.22 is 1, Z.sup.23 is a single bond,
--(CH.sub.2).sub.2-- or --COO--, Z.sup.24 is a single bond, --COO--
or --C.ident.C--, X.sup.22 is F, Cl, CF.sub.3, OCF.sub.3 or
OCF.sub.2H, at least one of Y.sup.23 and Y.sup.24 is F and each of
W.sup.21 and W.sup.22 is independently H or F, (3) a compound in
which in the general formula (II-3) R.sup.23 is an alkyl or alkenyl
group having 2 to 5 carbon atoms, one of Z.sup.25 and Z.sup.26 is a
single bond and the other is a single bond, --COO-- or
--C.ident.C--, X.sup.23 is F, at least one of Y.sup.25 and Y.sup.26
is F and W.sup.23 to W.sup.26 are H or one or more of them are F,
and (4) a compound in which in the general formulae (II-1) and
(II-2) the rings A.sup.21 to A.sup.23 are trans-1,4-cyclohexylene
and at least one of the hydrogen atoms in said ring is replaced by
deuterium atom; and
[0044] wherein the total content of these compounds in said liquid
crystal component B is from 10 to 100% by weight.
[0045] 10. The nematic liquid crystal composition described in any
one of the aforementioned items 5 to 9, wherein said liquid crystal
component C contains 1 to 15 compounds selected from the group
consisting of compounds represented by the general formulae (III-1)
to (III-4): 6
[0046] wherein each of R.sup.31 to R.sup.34 independently
represents an alkyl or alkoxy group having 1 to 7 carbon atoms or
an alkenyl or alkenyloxy group having 2 to 7 carbon atoms, wherein
said alkyl group, alkoxy group, alkenyl group or alkenyloxy group
may be unsubstituted or may have one F, CH.sub.3 or CF.sub.3 as a
substituent group, and/or at least one of CH.sub.2 groups existing
in said alkyl group, alkoxy group, alkenyl group or alkenyloxy
group may be substituted each independently with --O--, --CO-- or
--COO-- where O atoms are not directly linked to each other, each
of Y.sup.31 to Y.sup.36 independently represents H or F, or
Y.sup.33 and Y.sup.36 may also be --CH.sub.3, each of W.sup.31 to
W.sup.39 independently represents H, F or Cl, each of Z.sup.31 to
Z.sup.36 independently represents a single bond, --COO--, --OCO--,
--CH.sub.2O--, --OCH.sub.2--, --(CH.sub.2).sub.2--,
--(CH.sub.2).sub.4--, --CH.dbd.CH--(CH.sub.2).sub.2--,
--(CH.sub.2).sub.2--CH.dbd.CH--, --CH.dbd.N--,
--CH.dbd.N--N.dbd.CH-- or --N(O).dbd.N--, wherein each of Z.sup.31
and Z.sup.34 to Z.sup.36 may also be --CH.dbd.CH--, --CF.dbd.CF--
or --C.ident.C--, each of the rings A.sup.31 to A.sup.35
independently represents trans-1,4-cyclohexylene,
trans-1,4-cyclohexenyle- ne or trans-1,3-dioxane-2,5-diyl, wherein
each of the rings A.sup.31 and A.sup.33 to A.sup.35 may also be
1,4-phenylene, 2- or 3-fluoro-1,4-phenylene,
2,3-difluoro-1,3-phenylene or 3,5-difluoro-1,4-phenylene and, in
the case of trans-1,4-cyclohexylene, at least one of the hydrogen
atoms in said ring may be replaced by deuterium atom, each of
k.sup.31 to k.sup.35 independently represents 0 or 1 wherein
k.sup.34+k.sup.35 is 0 or 1, and the atoms which constitute the
compounds of said general formulae (III-1) to (III-4) may be
replaced by their isotopic atoms.
[0047] 11. The nematic liquid crystal composition described in the
aforementioned item 10, wherein said liquid crystal component C
contains 1 to 15 compounds selected from the group consisting of
the compounds represented by the general formula (III-1), (III-2)
or (III-3), and the total content of these compounds in said liquid
crystal component C is from 10 to 100% by weight.
[0048] 12. The nematic liquid crystal composition described in the
aforementioned item 10, wherein said liquid crystal component C
contains 1 to 15 or more compounds selected from the group
consisting of (1) a compound in which each of R.sup.31 to R.sup.34
in the general formulae (III-1) to (III-4) is independently an
alkenyl group having 2 to 5 carbon atoms, (2) a compound in which
each of R.sup.35 to R.sup.38 in the general formulae (III-1) to
(III-4) is independently a straight chain alkenyl or alkenyloxy
group having 2 to 7 carbon atoms, (3) a compound in which in the
general formula (III-1) k.sup.31 is 0 and Z.sup.32 is a single bond
or --(CH.sub.2).sub.2--, (4) a compound in which k.sup.31 in the
general formula (III-1) is 1, (5) a compound represented by the
general formula (III-2), (6) a compound in which in the general
formula (III-3) at least one of Y.sup.34, Y.sup.35 and W.sup.34 to
W.sup.36 is F and Y.sup.33 is F or --CH.sub.3, (7) a compound in
which in the general formula (III-3) k.sup.33 is 0 and Z.sup.36 is
a single bond, (8) a compound in which in the general formula
(III-3) k.sup.33 is 1 and Z.sup.35 is a single bond, --OCO--,
--CH.sub.2O--, --OCH.sub.2--, --(CH.sub.2).sub.2--,
--(CH.sub.2).sub.4--, --CH.dbd.CH--(CH.sub.2).sub.2- --,
--(CH.sub.2).sub.2--CH.dbd.CH--, --CH.dbd.N--,
--CH.dbd.N--N.dbd.CH--, --N(O).dbd.N--, --CH.dbd.CH-- or
--CF.dbd.CF--, (9) a compound in which in the general formula
(III-3) Z.sup.35 is --COO-- or --C.ident.C-- and Z.sup.36 is
--OCO--, --CH.sub.2O--, --OCH.sub.2--, --(CH.sub.2).sub.2--,
--(CH.sub.2).sub.4--, --CH.dbd.CH--(CH.sub.2).sub.2--,
--(CH.sub.2).sub.2--CH.dbd.CH--, --CH.dbd.N--,
--CH.dbd.N--N.dbd.CH--, --N(O).dbd.N--, --CH.dbd.CH--,
--CF.dbd.CF-- or --C.ident.C--, (10) a compound represented by the
general formula (III-4), and (11) a compound in which in the
general formulae (III-1) to (III-4) the rings A.sup.31 to A.sup.35
are trans-1,4-cyclohexylene and at least one of the hydrogen atoms
in said ring is replaced by deuterium atom.
[0049] 13. The nematic liquid crystal composition described in the
aforementioned item 10, wherein said liquid crystal component C
contains 1 to 15 compounds selected from the group consisting of
(1) a compound in which in the general formula (III-1) R.sup.31 is
an alkyl group having 1 to 5 carbon atoms or an alkenyl group
having 2 to 5 carbon atoms, R.sup.35 is an alkyl or alkoxy group
having 1 to 5 carbon atoms or an alkenyl or alkenyloxy group having
2 to 5 carbon atoms, k.sup.31 is 0 and Z.sup.32 is a single bond,
--COO-- or --(CH.sub.2).sub.2--, (2) a compound in which in the
general formula (III-1) k.sup.31 is 1, the ring A.sup.31 is
trans-1,4-cyclohexylene and one of Z.sup.31 and Z.sup.32 is a
single bond and the other is --COO-- or --(CH.sub.2).sub.2--, (3) a
compound in which in the general formula (III-2) R.sup.32 is an
alkyl group having 1 to 5 carbon atoms or an alkenyl group having 2
to 5 carbon atoms, R.sup.36 is an alkyl or alkoxy group having 1 to
5 carbon atoms or an alkenyl or alkenyloxy group having 2 to 5
carbon atoms, the ring A.sup.32 is trans-1,4-cyclohexylene or
trans-1,4-cyclohexenylene, k.sup.32 is 0 and Z.sup.33 is a single
bond, --COO-- or --(CH.sub.2).sub.2--, (4) a compound in which in
the general formula (III-2) k.sup.32 is 1 and one of Z.sup.33 and
Z.sup.34 is a single bond, (5) a compound in which in the general
formula (III-3) R.sup.33 is an alkyl group having 1 to 5 carbon
atoms or an alkenyl group having 2 to 5 carbon atoms, R.sup.37 is
an alkyl or alkoxy group having 1 to 5 carbon atoms or an alkenyl
or alkenyloxy group having 2 to 5 carbon atoms, k.sup.33 is 0 and
Z.sup.36 is a single bond, --C.ident.C-- or --CH.dbd.N--N.dbd.CH--,
(6) a compound in which in the general formula (III-3) k.sup.33 is
1, Z.sup.35 is a single bond, --(CH.sub.2).sub.2--, --COO-- or
--C.ident.C-- and Z.sup.36 is a single bond, --COO-- or
--C.ident.C--, (7) a compound in which in the general formula
(III-3) one of Z.sup.35 and Z.sup.36 is a single bond and the other
is a single bond or --C.ident.C-- and at least one of W.sup.34 and
W.sup.35 is F, (8) a compound in which in the general formula
(III-3) either one of Y.sup.35 and Y.sup.36 is substituted with F
or CH.sub.3, and (9) a compound in which in the general formula
(III-4) R.sup.34 is an alkyl group having 1 to 5 carbon atoms or an
alkenyl group having 2 to 5 carbon atoms, R.sup.38 is an alkyl or
alkoxy group having 1 to 5 carbon atoms or an alkenyl or alkenyloxy
group having 2 to 5 carbon atoms and k.sup.34+k.sup.35 is 0, and
wherein the total content of these compounds in said liquid crystal
component C is from 10 to 100% by weight.
[0050] 14. The nematic liquid crystal composition described in any
one of the aforementioned items 5 to 13, wherein said liquid
crystal composition contains 1 to 10 compounds having a core
structure of four six-membered rings and having a liquid crystal
phase-isotropic liquid phase transition temperature of 100.degree.
C. or more.
[0051] 15. The nematic liquid crystal composition described in any
one of the aforementioned items 5 to 14, wherein said liquid
crystal composition has a birefringence of from 0.08 to 0.195, an
elastic constant ratio K.sub.33/K.sub.11 of from 1.1 to 4.0, a
nematic phase-isotropic liquid phase transition temperature of from
50 to 150.degree. C. and a crystal phase-, smectic phase- or glass
phase-nematic phase transition temperature of from -200.degree. C.
to 0.degree. C.
[0052] 16. The nematic liquid crystal composition described in any
one of the aforementioned items 5 to 15, wherein said liquid
crystal composition further contains a compound having an optically
active group which shows an induced helical pitch of from 0.5 to
1,000 .mu.m.
[0053] 17. An active matrix, twisted nematic or super twisted
nematic liquid crystal display system comprising the nematic liquid
crystal composition described in the aforementioned item 16.
BRIEF DESCRIPTION OF THE DRAWING
[0054] FIG. 1 is a graph showing a relationship between viscosity
(.eta.) at 20.degree. C. and threshold voltage (Vth), measured in
Example 7 and Comparative Example 4.
DETAILED DESCRIPTION OF THE INVENTION
[0055] The following describes an example of the present
invention.
[0056] The liquid crystal composition of the present invention
contains component A as an essential component which comprises
compounds selected from the compounds represented by the general
formulae (I-1) to (I-18). The component A is characterized in that
it is constructed by classifying it into groups A1 to A6. The
groups A1 to A6 are classified by dividing the compounds of general
formulae (I-1) to (I-18) into a group having
3,5-difluoro-4-cyanophenyl group, a group having
3-fluoro-4-cyanophenyl group and a group having 4-cyanophenyl group
taking note of the polar groups and further into a group having for
example an alkenyl group and a group having for example an alkyl
group taking note of the side chain group. The liquid crystal
component A is selected from the groups A1 to A6. These groups may
be selected as one group, two groups or three or more groups in
response to each purpose. The present invention has found that its
objects can be achieved by grouping the compounds of general
formulae (I-1) to (I-18) in view of the above points, and
constituting the liquid crystal component A in such a manner that
characteristics of these groups become more suitable. More
illustratively, when the liquid crystal component A having the
aforementioned characteristics is blended in a liquid crystal
composition, the resulting mixture shows excellent characteristics
which cannot be found in the conventional driving voltage-reducing
liquid crystal compounds, because it shows a relatively good
nematic phase-isotropic liquid phase transition temperature and has
an effect to reduce driving voltage while keeping or without
spoiling the response property.
[0057] The liquid crystal composition of the present invention also
has the following characteristics. The liquid crystal component A
of the present invention has a feature in that it has markedly
large dielectric anisotropy At. Because of this, the liquid crystal
composition of the present invention has a feature in that driving
can be effected at a low voltage due to the ability to adjust the
dielectric anisotropy .DELTA..epsilon. within a wide range. In
general, a compound having markedly large dielectric anisotropy
.DELTA..epsilon. also has a disadvantage of causing high viscosity.
The present invention, however, has found an effect that lower
viscosity can be achieved for the size of dielectric anisotropy, by
a combination of the composition in which it contains the
aforementioned liquid crystal component A, 0 to 95% by weight of a
liquid crystal component B composed of compounds having a
dielectric anisotropy of +2 or more and 0 to 95% by weight of a
liquid crystal component C composed of compounds having a
dielectric anisotropy of from -10 or more to less than +2, wherein
the total amount of the liquid crystal component B and liquid
crystal component C is from 30 to 95% by weight. Also, when mixed
with a liquid crystal material consisting of the above-described
liquid crystal component B and liquid crystal component C,
operating temperature range of the liquid crystal component A can
be adjusted more widely for example by reducing solid phase- or
smectic phase-nematic phase transition temperature or prolonging
storage time at a low temperature.
[0058] The liquid crystal component A contains one or more
compounds selected from the compounds of general formulae (I-1) to
(I-18), and it is desirable to constitute the component with 1 to
20 compounds in response to each purpose. In that case, one or more
compounds can be selected from the same group, but it also is
possible to select a plurality of compounds from compounds
represented by the same general formula or from two or three
different general formulae. The compounds selected from the same
group can be constituted by 1 to 20 species, but more desirably by
1 to 10 species.
[0059] The compounds of group A3 and A6, when strictly compared
with compounds of other groups, have excellent effect to reduce
driving voltage, but have a tendency to worsen response property
and make nematic phase-isotropic liquid phase transition
temperature lower. In consequence, it is desirable to reduce the
number of the compounds of group A3 and group A6 as small as
possible; illustratively, it is desirable to constitute them with 1
to 10 species, more desirably with 1 to 5 species, most desirably
with 3, 2 or 1 species.
[0060] More preferred modes of the compounds represented by the
general formulae (I-1) to (I-18) are shown in the following. More
preferred mode of the side chain group R.sup.11 is general formulae
(I-a) to (I-ag) shown in the following, and more preferred mode of
the side chain group R.sup.12 is general formulae (I-ah) to (I-bc)
shown in the following. Compounds represented by these groups are
useful.
1 (I-a) C.sub.2H.sub.5-- (I-b) C.sub.3H.sub.7-- (I-c)
C.sub.4H.sub.9-- (I-d) C.sub.5H.sub.11-- (I-e) C.sub.6H.sub.13--
(I-f) C.sub.7H.sub.15-- (I-g) C.sub.2H.sub.5O-- (I-h)
C.sub.3H.sub.7O-- (I-i) C.sub.4H.sub.9O-- (I-j) C.sub.5H.sub.11O--
(I-k) C.sub.6H.sub.13O-- (I-l) C.sub.7H.sub.15O-- (I-m)
C.sub.2H.sub.5COO-- (I-n) C.sub.3H.sub.7COO-- (I-o)
C.sub.4H.sub.9COO-- (I-p) C.sub.5H.sub.11COO-- (I-q)
C.sub.6H.sub.13COO-- (I-r) C.sub.7H.sub.15COO-- (I-s)
CH.sub.3OCH.sub.2-- (I-t) CH.sub.3OC.sub.2H.sub.4-- (I-u)
CH.sub.3OC.sub.3H.sub.6-- (I-v) CH.sub.3OC.sub.4H.sub.8-- (I-w)
CH.sub.3OC.sub.5H.sub.10-- (I-x) C.sub.2H.sub.5OCH.sub.2-- (I-y)
C.sub.2H.sub.5OC.sub.2H.sub.4-- (I-z)
C.sub.2H.sub.5OC.sub.3H.sub.6-- (I-aa) C.sub.2H.sub.5OC.sub.4H.su-
b.8-- (I-ab) C.sub.2H.sub.5OC.sub.5H.sub.10-- (I-ac)
C.sub.3H.sub.7OCH.sub.2-- (I-ad) C.sub.3H.sub.7OC.sub.2H.sub.4--
(I-ae) C.sub.3H.sub.7OC.sub.3H.sub.6-- (I-af)
C.sub.3H.sub.7OC.sub.4H.sub.8-- (I-ag) C.sub.3H.sub.7OC.sub.5H.su-
b.10-- (I-ah) CH.sub.2.dbd.CH-- (I-ai) CH.sub.3CH.dbd.CH-- (I-aj)
C.sub.2H.sub.5CH.dbd.CH-- (I-ak) C.sub.3H.sub.7CH.dbd.CH-- (I-al)
CH.sub.2.dbd.CHC.sub.2H.sub.4-- (I-am)
CH.sub.3CH.dbd.CHC.sub.2H.sub.4-- (I-an) CH.sub.2.dbd.CHCH.sub.2--
(I-ao) CH.sub.2.dbd.CHO-- (I-ap) CH.sub.3CH.dbd.CHO-- (I-aq)
C.sub.2H.sub.5CH.dbd.CHO-- (I-ar) C.sub.3H.sub.7CH.dbd.CHO-- (I-as)
CH.sub.2.dbd.CHC.sub.2H.sub.4O-- (I-at) CH.sub.3CH.dbd.CHC.sub.2H-
.sub.4O-- (I-au) CH.sub.2.dbd.CHCH.sub.2O-- (I-av) CHF.dbd.CH--
(I-aw) CH.sub.2.dbd.CF-- (I-ax) CF.sub.2.dbd.CH-- (I-av)
CHF.dbd.CF-- (I-az) CHF.dbd.CHC.sub.2H.sub.4-- (I-ba)
CH.sub.2.dbd.CFC.sub.2H.sub.4-- (I-bb)
CF.sub.2.dbd.CHC.sub.2H.sub.4-- (I-bc)
CHF.dbd.CFC.sub.2H.sub.4--
[0061] In this connection, each of the compounds used in the
following was thoroughly purified by removing impurities using
distillation, column purification, recrystallization and the like
techniques.
[0062] In describing further in detail, it is desirable to use the
following compounds in the liquid crystal component A to obtain the
effects of the present invention.
[0063] In the general formulae (I-1) to (I-9),
[0064] (I-i): preferred are compounds in which R.sup.11 is an alkyl
group having 2 to 7 carbon atoms, illustratively, compounds having
basic structures of the general formulae (I-1) to (I-9) and side
chain groups of (I-a) to (I-l) and (I-s) to (I-ag), more preferably
having side chain groups of (I-a) to (I-f), (I-s) to (I-x) and
(I-ac). Since these compounds have the effect to reduce driving
voltage, and elastic constants and their ratios K.sub.33/K.sub.11
and K.sub.33/K.sub.22 can be controlled, further improved
electro-optical characteristics of TN-LCD, STN-LCD and the like
devices can be obtained.
[0065] Also, in the general formulae (I-10) to (I-18),
[0066] (I-ii): preferred are compounds in which R.sup.12 is an
alkenyl group having 2 to 7 carbon atoms, illustratively, compounds
having basic structures of the general formulae (I-10) to (I-18)
and side chain groups of (I-ah) to (I-bc), more preferably having
side chain groups of (I-al) to (I-an), (I-as) to (I-au) and (I-az)
to (I-bc). Most preferred is a nematic liquid crystal composition
which contains 1 to 10 compounds in which R.sup.12 is represented
by CH.sub.2.dbd.CH--, CH.sub.2.dbd.CH--(CH.sub.2).sub.2--,
CH.sub.2.dbd.CH--(CH.sub.2).sub.4--, CH.sub.3CH.dbd.CH--,
CH.sub.3CH.dbd.CH--(CH.sub.2).sub.2-- or
CH.sub.3CH.dbd.CH--(CH.sub.2).sub.4--. Since these compounds have
the effect to reduce driving voltage while keeping or without
worsening nematic phase-isotropic liquid phase transition
temperature and response property, operating temperature range can
be expanded through the improvement of miscibility and low
temperature shelf life of the liquid crystal composition and
elastic constants and their ratios K.sub.33/K.sub.11 and
K.sub.33/K.sub.22 can be controlled, so that electro-optical
characteristics of TN-LCD, STN-LCD and the like devices with
improved sharpness, response or temperature characteristics can be
obtained.
[0067] In order to cause the effect to reduce driving voltage or
its temperature dependency or frequency dependency of driving
voltage in response to high duty,
[0068] (I-iii): it is desirable to use mainly compounds represented
by the group A3 and/or group A6 having 3,5-difluoro-4-cyanophenyl
group and compounds represented by the group A2 and/or group A5
having 3-fluoro-4-cyanophenyl group. In that case, it is more
desirable to select compounds in which R.sup.11 is (I-a) to (I-f),
(I-s) to (I-x) or (I-ac) and compounds in which R.sup.12 is (I-al)
to (I-an), (I-as) to (I-au) or (I-az) to (I-bc).
[0069] In order to reduce driving voltage while keeping or without
worsening nematic phase-isotropic liquid phase transition
temperature and response property,
[0070] (I-iv): it is desirable to use mainly compounds of the
general formulae (I-3), (I-6), (I-12) and (I-15) having
3,5-difluoro-1,4-phenylen- e group and compounds of the general
formulae (I-2), (I-5), (I-18), (I-11), (I-14) and (I-17) having
3-fluoro-1,4-phenylene group.
[0071] A liquid crystal component A which contains one or two or
more of compounds selected from these subgroups (I-i) to (I-iv) is
desirable. Particularly, a liquid crystal component A in which
compounds having alkenyl groups as the side chain groups are
selectively combined or a liquid crystal component A in which
compounds having alkyl groups and alkenyl groups are simultaneously
selected are desirable in terms of the sharpness and response of
STN-LCD or temperature characteristics thereof. Also, a liquid
crystal component A in which compounds having
3,5-difluoro-4-cyanophenyl group as the polar group and compounds
having 3-fluoro-4-cyanophenyl group are simultaneously selected is
desirable, because driving voltage can be reduced while improving
problems concerning miscibility. In view of such points, it is
desirable that the liquid crystal component A is composed of groups
A1 to A6 and satisfies at least one of the following
conditions.
[0072] (i) The liquid crystal component A contains at least one
compound selected from the compounds represented by the general
formulae (I-11), (I-12), (I-14), (I-15), (I-17) and (I-18), and the
content of the compound in the liquid crystal component A is from 5
to 100% by weight. This construction can exert the aforementioned
effects concerning subgroups (I-ii) to (I-iv).
[0073] (ii) The liquid crystal component A contains 1 to 10 of the
compounds represented by the group A5 and 1 to 10 of the compounds
represented by the group A4 and/or group A6, and the total content
of both of these compounds in the liquid crystal component A is
from 5 to 100% by weight.
[0074] (iii) The liquid crystal component A contains 1 to 10 of the
compounds represented by the group A6 and 1 to 10 of the compounds
represented by the group A4 and/or group A5, and the total content
of both of these compounds in the liquid crystal component A is
from 5 to 100% by weight.
[0075] In the above constructions, a combination of a group having
3,5-difluoro-4-cyanophenyl group with a group having
3-fluoro-4-cyanophenyl group and/or a group having 4-cyanophenyl
group is used taking note of the polar groups, and a group having
an alkenyl group is used as the main component taking note of the
side chain group. This construction can exert the aforementioned
effects concerning subgroups (I-ii) to (I-iv).
[0076] (iv) The liquid crystal component A contains 1 to 10 of the
compounds represented by the groups A4 to A6 in which the side
chain group has an alkenyl group and 1 to 10 of the compounds
represented by the groups A1 to A3 in which the side chain group
has an alkyl group, and the total content of these compounds in the
liquid crystal component A is from 5 to 100% by weight.
[0077] (v) The liquid crystal component A contains 1 to 10 of the
compounds represented by the group A3 and/or group A6 having
3,5-difluoro-4-cyanophenyl group and 1 to 10 of the compounds
represented by the group A2 and/or group A5 having
3-fluoro-4-cyanophenyl group, wherein at least one of these
selected compounds belongs to the group A5 or group A6, and the
total content of these compounds in the liquid crystal component A
is from 5 to 100% by weight.
[0078] (vi) The liquid crystal component A contains 1 to 10 of the
compounds represented by the group A3 and/or group A6 having
3,5-difluoro-4-cyanophenyl group and 1 to 10 of the compounds
represented by the group A1 and/or group A4 having 4-cyanophenyl
group, wherein at least one of these selected compounds belongs to
the group A4 or group A6, and the total content of these compounds
in the liquid crystal component A is from 5 to 100% by weight.
[0079] In the above constructions, a combination of a group having
3,5-difluoro-4-cyanophenyl group with a group having
3-fluoro-4-cyanophenyl group and/or a group having 4-cyanophenyl
group is used taking note of the polar groups, and a group having
an alkenyl group and a group having an alkyl group are jointly used
taking note of the side chain group. This construction can exert
the aforementioned effects concerning subgroups (I-i) to
(I-iv).
[0080] (vii) The liquid crystal component A contains 1 to 10 of the
compounds represented by the group A3 and/or group A6 having
3,5-difluoro-4-cyanophenyl group, 1 to 10 of the compounds
represented by the group A2 and/or group A5 having
3-fluoro-4-cyanophenyl group and 1 to 10 of the compounds
represented by the group A1 and/or group A4 having 4-cyanophenyl
group, and the total content of these compounds in the liquid
crystal component A is from 5 to 100% by weight.
[0081] In the above construction, a group having
3,5-difluoro-4-cyanopheny- l group, a group having
3-fluoro-4-cyanophenyl group and a group having 4-cyanophenyl group
are jointly used taking note of the polar groups. This construction
can exert the aforementioned effects concerning the subgroup
(I-iv).
[0082] According to the present invention, one or more compounds
optionally selected from the groups A1 to A6 can be included as the
liquid crystal component A, but the aforementioned effects can be
obtained even by a single compound. Preferably, depending on the
desired purpose, it may be constructed with the aforementioned
compounds (i) to (viii). Since the liquid crystal composition of
the present invention containing such a liquid crystal component A
can expand operating temperature range of the liquid crystal
display characteristics through the improvement of miscibility and
low temperature shelf life, improve reduction of driving voltage
and temperature changes thereof and achieve or improve relatively
quick response for a desired driving voltage, further improved
electro-optical characteristics, particularly more desirable low
temperature-dependency, can be added to TN-LCD, STN-LCD and the
like devices in which such a composition is used.
[0083] In addition to the aforementioned liquid crystal component
A, the liquid crystal composition of the present invention contains
a liquid crystal component B which contains at least one compound
having a dielectric anisotropy of +2 or more. In this connection,
the term "liquid crystal compound having a dielectric anisotropy of
+2 or more" as used herein means as follows. That is, the liquid
crystal compound has a rod-shaped chemical structure in which its
central part has a core structure having 1 to 4 six-membered rings,
six-membered rings positioned at both termini of the central part
in major axis direction have terminal groups substituted at
positions corresponding to the major axis of the liquid crystal
molecule and at least one of the terminal groups positioned at both
termini is a polar group such as --F, --Cl, --NO.sub.2, --CF.sub.3,
--OCF.sub.3, --OCHF.sub.2, --CN, --OCN, --NCS or the like group. By
such a structure, optical anisotropy of the liquid crystal layer
can be controlled at a desired value, electrical drive can be made
and operating temperature range can be expanded.
[0084] In the liquid crystal component B, at least 1 species,
preferably from 3 to 15 species, can be used as the compound having
a dielectric anisotropy of +2 or more. Also, it is desirable to use
the compound by optionally selecting from compounds having a
dielectric anisotropy of from +2 to +8, compounds having a
dielectric anisotropy of from +8 to +13, compounds having a
dielectric anisotropy of from +14 to +18 and compounds having a
dielectric anisotropy of +18 or more, by which desired driving
voltage and response characteristics can be obtained. In that case,
it is desirable to mix compounds having a dielectric anisotropy of
from +2 to +13 within the range of 10 or less species at the most,
to mix compounds having a dielectric anisotropy of from +14 to +18
within the range of 8 or less species at the most or to mix
compounds having a dielectric anisotropy of from +18 or more within
the range of 10 or less species at the most. The use of the liquid
crystal component B in the aforementioned manner gives temperature
characteristics of the display characteristics more desirable
effects. More illustratively, it improves driving voltage,
sharpness-related contrast and response or the like
temperature-dependency to more desirable levels.
[0085] In view of such points, more preferred modes of the basic
structures in the compounds represented by the general formulae
(II-1) to (II-4) are compounds represented by the following general
formulae (II-1a) to (II-4g). 7
[0086] Also, more preferred modes of the formulae (II-51) to
(II-54) in the side chain groups R.sup.21 to R.sup.24 are compounds
represented by the following general formulae (II-5a) to
(II-5bc).
2 (II-51) R.sup.21-- (II-52) R.sup.22-- (II-53) R.sup.23-- (II-54)
R.sup.24-- (II-5a) C.sub.2H.sub.5-- (II-5b) C.sub.3H.sub.7--
(II-5c) C.sub.4H.sub.9-- (II-5d) C.sub.5H.sub.11-- (II-5e)
C.sub.6H.sub.13-- (II-5f) C.sub.7H.sub.15-- (II-5g)
C.sub.2H.sub.5O-- (II-5h) C.sub.3H.sub.7O-- (II-5i)
C.sub.4H.sub.9O-- (II-5j) C.sub.5H.sub.11O-- (II-5k)
C.sub.6H.sub.13O-- (II-5l) C.sub.7H.sub.15O-- (II-5m)
C.sub.2H.sub.5COO-- (II-5n) C.sub.3H.sub.7COO-- (II-5o)
C.sub.4H.sub.9COO-- (II-5p) C.sub.5H.sub.11COO-- (II-5q)
C.sub.6H.sub.13COO-- (II-5r) C.sub.7H.sub.15COO-- (II-5s)
CH.sub.3OCH.sub.2-- (II-5t) CH.sub.3OC.sub.2H.sub.4-- (II-5u)
CH.sub.3OC.sub.3H.sub.6- -- (II-5v) CH.sub.3OC.sub.4H.sub.8--
(II-5w) CH.sub.3OC.sub.5H.sub.10-- (II-5x)
C.sub.2H.sub.5OCH.sub.2-- (II-5y) C.sub.2H.sub.5OC.sub.2H.sub.4--
(II-5z) C.sub.2H.sub.5OC.sub.3H.sub.6-- (II-5aa)
C.sub.2H.sub.5OC.sub.4H.- sub.8-- (II-5ab)
C.sub.2H.sub.5OC.sub.5H.sub.10-- (II-5ac) C.sub.3H.sub.7OCH.sub.2--
(II-5ad) C.sub.3H.sub.7OC.sub.2H.sub.4-- - (II-5ae)
C.sub.3H.sub.7OC.sub.3H.sub.6-- (II-5af)
C.sub.3H.sub.7OC.sub.4H.sub.8-- (II-5ag) C.sub.3H.sub.7OC.sub.5H.-
sub.10-- (II-5ah) CH.sub.2.dbd.CH-- (II-5ai) CH.sub.3CH.dbd.CH--
(II-5aj) C.sub.2H.sub.5CH.dbd.CH-- (II-5ak)
C.sub.3H.sub.7CH.dbd.CH-- (II-5al) CH.sub.2.dbd.CHC.sub.2H.sub.4--
(II-5am) CH.sub.3CH.sub.2.dbd.CHC- .sub.2H.sub.4-- (II-5an)
CH.sub.2.dbd.CHC.sub.2H.sub.5CH.dbd.CH-- (II-5ao)
CH.sub.2.dbd.CHO-- (II-5ap) CH.sub.3CH.dbd.CHO-- (II-5aq)
C.sub.2H.sub.5CH.dbd.CHO-- (II-5ar) C.sub.3H.sub.7CH.dbd.CHO--
(II-5as) CH.sub.2.dbd.CHC.sub.2H.sub.4- O-- (II-5at)
CH.sub.3CH.sub.2.dbd.CHC.sub.2H.sub.4O-- (II-5au)
CH.sub.2.dbd.CHC.sub.2H.sub.5CH.dbd.CHO-- (II-5av) CHF.dbd.CH--
(II-5aw) CH.sub.2.dbd.CF-- (II-5ax) CF.sub.2.dbd.CH-- (II-5ay)
CHF.dbd.CF-- (II-5az) CHF.dbd.CHC.sub.2H.sub.4-- (II-5ba)
CH.sub.2.dbd.CFC.sub.2H.sub.4- -- (II-5bb)
CF.sub.2.dbd.CHC.sub.2H.sub.4-- (II-5bc)
CHF.dbd.CFC.sub.2H.sub.4--
[0087] Also, more preferred modes of the partial structural
formulae (II-61) to (II-64) of 1,4-phenylene having a polar group
are compounds represented by the following general formulae (II-6a)
to (II-6r). 8
[0088] In this connection, each of the compounds used in the
following was thoroughly purified by removing impurities using
distillation, column purification, recrystallization and the like
techniques.
[0089] In describing further in detail, when a general purpose
liquid crystal composition is desired, it is desirable to use the
following compounds in the liquid crystal component B, and the
effects of the present invention can be obtained by the combination
of such a liquid crystal component B with the liquid crystal
component A.
[0090] Among compounds of the aforementioned general formulae
(II-1) to (II-4),
[0091] (II-ai): compounds in which R.sup.21 to R.sup.24 are alkenyl
groups having 2 to 5 carbon atoms, illustratively, compounds in
which they have the basic structures of the general formulae
(II-1a) to (II-4g), side chain groups of (II-5ah) to (II-5bc) and
polar group partial structures of general formulae (II-6a) to
(II-6r), more preferably compounds having the basic structures of
general formulae (II-1a) to (II-1l) or (II-2i) to (II-2ae), can
provide further improved electro-optical characteristics of
STN-LCD, TFT-LCD, PDLC, PN-LCD and the like devices, and
[0092] (II-aii): compounds in which X.sup.21 to X.sup.24 are F, Cl
or --OCF.sub.3, illustratively, compounds in which they have the
basic structures of the general formulae (II-1a) to (II-4g), side
chain groups of (II-5ah) to (II-5bc) and polar group partial
structures of general formulae (II-6d) to (II-6i) or (II-6m) to
(II-6o), more preferably compounds having the basic structures of
general formulae (II-1a) to (II-1l), (II-2f) to (II-2q), (II-2u) to
(II-2w) or (II-2ab) to (II-4f) and polar group partial structures
of general formulae (II-6d) to (II-6i) or (II-6m) to (II-6o), can
provide TFT-LCD, PDLC, PN-LCD and the like devices for active use
with reduced driving voltage and excellent high voltage holding
ratio when these compounds are substantially used as the main
component and also can provide TN-LCD, STN-LCD, PDLC, PN-LCD and
the like devices with excellent driving voltage, sharpness and
response or their temperature characteristics when compounds in
which X.sup.21 to X.sup.24 are F and CN are jointly used
substantially as the main component.
[0093] Among compounds of the aforementioned general formula
(II-1),
[0094] (II-aiii): compounds in which Z.sup.22 is
--(CH.sub.2).sub.2-- or --(CH.sub.2).sub.4--, illustratively,
compounds having basic structures of the general formulae (II-1c),
(II-1d), (II-1g) and (II-1h), side chain groups of (II-5a) to
(II-5bc) and polar group partial structures of general formulae
(II-6a) to (II-6r), or
[0095] (II-aiv): compounds in which k.sup.21 is 1, illustratively,
compounds having basic structures of the general formulae (II-1e)
to (II-1l), side chain groups of (II-5a) to (II-5bc) and polar
group partial structures of general formulae (II-6a) to (II-6r),
are suitable for use in a case which requires low driving voltage
and relatively small birefringence.
[0096] Among compounds of the aforementioned general formula
(II-2),
[0097] (II-av): compounds in which at least one of Y.sup.23,
Y.sup.24, W.sup.21 and W.sup.22 is F, illustratively, compounds
having basic structures of general formulae (II-2a), (II-2c),
(II-2f), (II-2i), (II-2l), (II-2o), (II-2r), (II-2u), (II-2x),
(II-2y), (II-2ab) and (II-2ac), side chain groups of (II-5a) to
(II-5bc) and polar group partial structures of general formulae
(II-6b), (II-6c), (II-6e), (II-6f), (II-6h), (II-6i), (II-6k),
(II-6l), (II-6n), (II-6o), (II-6q) and (II-6r), or compounds having
basic structures of general formulae (II-2b), (II-2d), (II-2e),
(II-2g), (II-2h), (II-2j), (II-2k), (II-2m), (II-2n), (II-2p),
(II-2q), (II-2s), (II-2t), (II-2v), (II-2w), (II-2z), (II-2aa),
(II-2ad) and (II-2ae), side chain groups of (II-5a) to (II-5bc) and
polar group partial structures of general formulae (II-6a) to
(II-6r), are suitable for reducing driving voltage,
[0098] (II-avi): compounds in which k.sup.22 is 1 and Z.sup.24 is
--C.ident.C--, illustratively, compounds having basic structures of
general formulae (II-2o) to (II-2q) and (II-2ab) to (II-2ae), side
chain groups of (II-5a) to (II-5bc) and polar group partial
structures of general formulae (II-6a) to (II-6r), are suitable for
a case which requires low driving voltage and relatively large
birefringence, and
[0099] (II-avii): compounds in which Z.sup.23 is a single bond or
--(CH.sub.2).sub.2-- and Z.sup.24 is --COO--, illustratively,
compounds having basic structures of general formulae (II-2l) to
(II-2n), (II-2r) to (II-2t) and (II-2y) to (II-2aa), side chain
groups of (II-5a) to (II-5bc) and polar group partial structures of
general formulae (II-6a) to (II-6r), are suitable for use in a case
which requires low driving voltage.
[0100] Among compounds of the aforementioned general formula
(II-3),
[0101] (II-aviii): compounds in which at least one of Y.sup.25,
Y.sup.26, W.sup.23 to W.sup.26 is F, illustratively, compounds
having basic structures of general formulae (II-3a), (II-3j),
(II-3k), (II-3s) and (II-3t) side chain groups of (II-5a) to
(II-5bc) and polar group partial structures of general formulae
(II-6b), (II-6c), (II-6e), (II-6f), (II-6h), (II-6i), (II-6k),
(II-6l), (II-6n), (II-6o), (II-6q) and (II-6r), or compounds having
basic structures of general formulae (II-3b) to (II-3i), (II-3l) to
(II-3r) and (II-3u) to (II-3x), side chain groups of (II-5a) to
(II-5bc) and polar group partial structures of general formulae
(II-6a) to (II-6r), are suitable for reducing driving voltage,
[0102] (II-aix): compounds in which Z.sup.26 is --C.ident.C--,
illustratively, compounds having basic structures of general
formulae (II-3k) to (II-3r), side chain groups of (II-5a) to
(II-5bc) and polar group partial structures of general formulae
(II-6a) to (II-6r), are suitable for a case which requires low
driving voltage and relatively large birefringence, and
[0103] (II-ax): compounds in which Z.sup.25 is a single bond or
--C.ident.C-- and Z.sup.26 is --COO--, illustratively, compounds
having basic structures of general formulae (II-3j) and (II-3y),
side chain groups of (II-5a) to (II-5bc) and polar group partial
structures of general formulae (II-6a) to (II-6r).
[0104] (II-axi): Compounds represented by the aforementioned
general formula (II-4), illustratively, compounds having basic
structures of general formulae (II-4a) to (II-4g), side chain
groups of (II-5a) to (II-5bc) and polar group partial structures of
general formulae (II-6a) to (II-6r).
[0105] Among compounds of the aforementioned general formulae
(II-1) and (II-2),
[0106] (II-axii): the rings A.sup.21 to A.sup.24 are
trans-1,4-cyclohexylene, and hydrogen atoms of the rings are
replaced by deuterium atoms, illustratively, compounds having basic
structures of general formulae (II-1a) to (II-1l) and (II-2i) to
(II-2ae), side chain groups of (II-5a) to (II-5bc) and polar group
partial structures of general formulae (II-6a) to (II-6r).
[0107] A nematic liquid crystal composition which contains one or
two or more compounds selected from the compounds represented by
these subgroups (II-ai) to (II-axii) is desirable.
[0108] Also, when a liquid crystal composition suitable for use in
TN-LCD or STN-LCD is desired, it is desirable to use the following
compounds in the liquid crystal component B, and the effects of the
present invention can be obtained by the combination of such a
liquid crystal component B with the liquid crystal component A.
[0109] Among compounds represented by the aforementioned general
formula (II-1) in which R.sup.21 is an alkyl or alkenyl group
having 2 to 5 carbon atoms,
[0110] (II-bi): compounds in which k.sup.21 is 0 and X.sup.21 is
--CN, illustratively, compounds having basic structures of general
formulae (II-1a) to (II-1d), side chain groups of (II-5a) to
(II-5d), (II-5ah) to (II-5am) and (II-5av) to (II-5bc) and polar
group partial structures of general formulae (II-6a) to (II-6r),
and
[0111] (II-bii): compounds in which k.sup.21 is 1, X.sup.21 is F or
--CN, and Y.sup.21 and Y.sup.22 are H or F, illustratively,
compounds having basic structures of general formulae (II-1e) to
(II-1l), side chain groups of (II-5a) to (II-5d), (II-5ah) to
(II-5am) and (II-5av) to (II-5bc) and polar group partial
structures of general formulae (II-6a) to Pi (II-6f).
[0112] Among compounds represented by the aforementioned general
formula (II-2) in which R.sup.22 is an alkyl or alkenyl group
having 2 to 5 carbon atoms,
[0113] (II-biii): compounds in which k.sup.22 is 0, X.sup.22 is
--CN, and Y.sup.23, Y.sup.24, W.sup.21 and W.sup.22 are H or F,
illustratively, compounds having basic structures of general
formulae (II-2a) to (II-2h), side chain groups of (II-5a) to
(II-5d), (II-5ah) to (II-5am) and (II-5av) to (II-5bc) and polar
group partial structures of general formulae (II-6a) to (II-6c),
and
[0114] (II-biv): compounds in which k.sup.22 is 1, Z.sup.23 is a
single bond, --(CH.sub.2).sub.2-- or --COO--, Z.sup.24 is a single
bond, --COO-- or --C.ident.C--, X.sup.22 is F or --CN and Y.sup.23,
Y.sup.24, W.sup.21 and W.sup.22 are H or F, illustratively,
compounds having basic structures of general formulae (II-2i) and
(II-2ae), side chain groups of (II-5a) to (II-5d), (II-5ah) to
(II-5am) and (II-5av) to (II-5bc) and polar group partial
structures of general formulae (II-6a) to (II-6f).
[0115] Among compounds represented by the aforementioned general
formula (II-3) in which R.sup.23 is an alkyl or alkenyl group
having 2 to 5 carbon atoms,
[0116] (II-bv): one of Z.sup.25 and Z.sup.26 is a single bond and
the other is a single bond, --COO-- or --C.ident.C--,
illustratively, compounds having basic structures of general
formulae (II-3a) to (II-3x), side chain groups of (II-5a) to
(II-5d), (II-5ah) to (II-5am) and (II-5av) to (II-5bc) and polar
group partial structures of general formulae (II-6a) to (II-6r),
and
[0117] (II-bvi): compounds in which Y.sup.25, Y.sup.26 and W.sup.23
to W.sup.25 are H or F, illustratively, compounds having basic
structures of general formulae (II-3a) to (II-3x), side chain
groups of (II-5a) to (II-5d), (II-5ah) to (II-5am) and (II-5av) to
(II-5bc) and polar group partial structures of general formulae
(II-6a) to (II-6r).
[0118] (II-bvii): Compounds of the aforementioned general formula
(II-4) in which R.sup.24 is an alkyl or alkenyl group having 2 to 7
carbon atoms and k.sup.23+k.sup.24 is 0, illustratively, compounds
having the basic structure of general formula (II-4a), side chain
groups of (II-5a) to (II-5f), (II-5ah) to (II-5am) and (II-5av) to
(II-5bc) and polar group partial structures of general formulae
(II-6a) to (II-6r).
[0119] (II-bviii): Compounds of the aforementioned general formulae
(II-1) and (II-2) in which rings A.sup.21 to A.sup.24 are
trans-1,4-cyclohexylene and hydrogen atoms of the rings are
replaced by deuterium atoms, illustratively, compounds having basic
structures of general formulae (II-1a) to (II-1l) and (II-2i) to
(II-2ae), side chain groups of (II-5a) to (II-5bc) and polar group
partial structures of general formulae (II-6a) to (II-6r).
[0120] A nematic liquid crystal composition which contains one or
two or more compounds selected from the compounds represented by
these subgroups (II-bi) to (II-bviii), wherein the total content of
these compounds is from 10 to 100% by weight as the liquid crystal
component B, is desirable.
[0121] Also, when a liquid crystal composition suitable for use in
TFT-LCD, IPS, PDLC, PN-LCD or the like device for active use is
desired, it is desirable to use the following compounds in the
liquid crystal component B, and the effects of the present
invention can be obtained by the combination of such a liquid
crystal component B with the liquid crystal component A
[0122] (II-ci): Compounds of the aforementioned general formula
(II-1) in which R.sup.21 is an alkyl or alkenyl group having 2 to 5
carbon atoms, k.sup.21 is 1, one of Z.sup.21 and Z.sup.22 is a
single bond and the other is a single bond, --COO--,
--(CH.sub.2).sub.2-- or --(CH.sub.2).sub.4--, X.sup.21 is F, Cl,
CF.sub.3, OCF.sub.3 or OCF.sub.2H and at least one of Y.sup.21 and
Y.sup.22 is F, illustratively, compounds having basic structures of
general formulae (II-1e) to (II-1k), side chain groups of (II-5a)
to (II-5d), (II-5ah) to (II-5am) and (II-5av) to (II-5bc) and polar
group partial structures of general formulae (II-6d) to
(II-6r).
[0123] (II-cii): Compounds of the aforementioned general formula
(II-2) in which R.sup.22 is an alkyl or alkenyl group having 2 to 5
carbon atoms, k.sup.22 is 1, Z.sup.23 is a single bond,
--(CH.sub.2).sub.2-- or --COO--, Z.sup.24 is a single bond, --COO--
or --C.ident.C--, X.sup.22 is F, Cl, CF.sub.3, OCF.sub.3 or
OCF.sub.2H, at least one of Y.sup.23 and Y.sup.24 is F and each of
W.sup.21 and W.sup.22 is H or F, illustratively, compounds having
basic structures of general formulae (II-2i) to (II-2ae), side
chain groups of (II-5a) to (II-5d), (II-5ah) to (II-5am) and
(II-5av) to (II-5bc) and polar group partial structures of general
formulae (II-6d) to (II-6r).
[0124] (II-ciii): Compounds of the aforementioned general formula
(II-3) in which R.sup.23 is an alkyl or alkenyl group having 2 to 5
carbon atoms, one of Z.sup.25 and Z.sup.26 is a single bond and the
other is a single bond, --COO-- or --C.ident.C--, X.sup.23 is F, at
least one of Y.sup.25 and Y.sup.26 is F and each of W.sup.23 to
W.sup.25 is H or at least one of them is F, illustratively,
compounds having basic structures of general formulae (II-3a) to
(II-3x), side chain groups of (II-5a) to (II-5d), (II-5ah) to
(II-5am) and (II-5av) to (II-5bc) and polar group partial
structures of general formulae (II-6e) and (II-6f).
[0125] (II-civ): Compounds of the aforementioned general formulae
(II-1) and (II-2) in which each of the rings A.sup.21 to A.sup.24
is trans-1,4-cyclohexylene and hydrogen atoms of these rings are
replaced by deuterium atoms, illustratively, compounds having basic
structures of general formulae (II-1a) to (II-1l) and (II-2i) to
(II-2ae), side chain groups of (II-5a) to (II-5bc) and polar group
partial structures of general formulae (II-6a) to (II-6r).
[0126] A nematic liquid crystal composition which contains one or
two or more compounds selected from the compounds represented by
these subgroups (II-ci) to (II-civ), wherein the total content of
these compounds is from 10 to 100% by weight as the liquid crystal
component B, is desirable.
[0127] Particularly preferred mode in compounds represented by the
general formulae (II-1) to (II-4) is a liquid crystal component B
which contains the following compounds.
[0128] (II-di): Compounds in which each of R.sup.21 to R.sup.24 is
an alkyl group having 2 to 7 carbon atoms. Compounds in which each
of R.sup.21 and R.sup.22 is an alkenyl group of
CH.sub.2.dbd.CH--(CH.sub.2).- sub.p (p=0 or 2).
[0129] Illustratively, it is desirable that compounds having basic
structures of the general formulae (II-1a), (II-1e), (II-2a),
(II-2c), (II-2d), (II-2i), (II-2l), (II-2o), (II-3a), (II-3l),
(II-4a) to (II-4c) and (II-4e) have these groups, because viscosity
and viscoelasticity can be reduced by adding at least one of such
compounds having alkyl and/or alkenyl groups to the liquid crystal
component B.
[0130] (II-dii): It is desirable to include at least one compound
selected from compounds in which X.sup.21 to X.sup.24 are F, Cl,
--OCF.sub.3 or --CN.
[0131] (II-diii): When quick response is an important object, it is
desirable to use compounds of general formulae (II-1a), (II-1e),
(II-2a), (II-2c), (II-2d), (II-2i), (II-2l), (II-2o), (II-3a),
(II-3l) and (II-4a) in which X.sup.21 to X.sup.24 are F,
--OCF.sub.3 or --CN, frequently in the liquid crystal component
B.
[0132] (II-div): When more larger birefringence is required, it is
desirable to use compounds of general formulae (II-2a) to (II-4d)
in which X.sup.22 to X.sup.24 are Cl, --OCF.sub.3 or --CN, and/or
compounds of general formulae (II-2f) to (II-2h), (II-2o) to
(II-2q), (II-2ab) to (II-2ae) and (II-3k) to (II-3x) in which each
of Z.sup.24 to Z.sup.26 is --C.ident.C--, frequently in the liquid
crystal component B.
[0133] (II-dv): When more lower driving voltage is required, it is
desirable to use compounds of general formulae (II-1a) to (II-4g)
in which X.sup.21 to X.sup.24 are F, Cl or --CN and Y.sup.21 to
Y.sup.24 are essentially F frequently in the liquid crystal
component B.
[0134] (II-dvi): Compounds of general formulae (II-1) and (II-2) in
which hydrogen atom in the cyclohexane ring is replaced by
deuterium atom can be used but, since such compounds are useful in
adjusting elastic constant of the liquid crystal composition and
controlling pre-tilt angle corresponding to the orientation film,
it is desirable to use at least one or more of the
deuterium-replaced compounds.
[0135] (II-dvii): Mixing ratio of two-ring compounds of general
formulae (II-1), (II-2) and (II-4) in which k.sup.21 to k.sup.24
are 0 to compounds of general formulae (II-1) and (II-2) in which
k.sup.21 and k.sup.22 are 1, compounds of general formula (II-4) in
which k.sup.23+k.sup.24 is 1 and/or three-ring compounds of general
formula (II-3) in the liquid crystal component B can be selected
optionally within the range of from 0:100 to 100:0, and when more
higher nematic phase-isotropic liquid phase transition temperature
is required, it is desirable to frequently use compounds of general
formulae (II-1) and (II-2) in which k.sup.21 and k.sup.22 are 1,
compounds of general formula (II-3) and/or compounds of general
formula (II-4) in which k.sup.23+k.sup.24 is 1.
[0136] A liquid crystal component B which contains these compounds
of (II-ai) to (II-dvii) is characterized by its ability to mix
thoroughly with the essential component, liquid crystal component
A, and particularly useful in controlling driving voltage in
response to each purpose and improving its temperature-dependency
or improving response property. Particularly, compounds of general
formulae (II-1a) to (II-1g), general formulae (II-2a) to (II-2q),
general formulae (II-2u) to (II-2x), general formulae (II-2ab) to
(II-2ae), general formulae (II-3a) to (II-3d), general formulae
(II-3l) to (II-3r) and general formulae (II-4a) to (II-14e) are
excellent in at least one of such effects, and these effects can be
obtained even by a small content of from 0.1 to 25% by weight based
on the total amount of the nematic liquid crystal composition of
the present invention.
[0137] The aforementioned effects of the liquid crystal component B
can also be obtained when the content of a liquid crystal component
C, which will be described in the following, is considerably small.
In order to obtain particularly low driving voltage, the content of
the liquid crystal component C can be set to 10% by weight or less.
In that case, it is desirable to reduce viscosity of the liquid
crystal component C as low as possible, because the driving voltage
hardly increases or increases within a narrow range and improving
effect of response time can be obtained efficiently. For example,
as a means for achieving this effect by the liquid crystal
component B when amount of the liquid crystal component C is small,
it is desirable to include in the liquid crystal component B any
one of the compounds of general formulae (II-1) to (II-4) in which
X.sup.21 to X.sup.24 are F, Cl or --OCF.sub.3, in which Y.sup.21 to
Y.sup.24 are F, in which Z.sup.24 and Z.sup.25 are --COO-- or
--C.ident.C-- or in which k.sup.11 is 1. Particularly preferred are
compounds of general formulae (II-1) to (II-4) in which X.sup.21 to
X.sup.24 are F, Cl --OCF.sub.3, or --CN and/or Y.sup.21 to Y.sup.23
are F.
[0138] In addition to the liquid crystal component A as the
essential component, the liquid crystal composition of the present
invention may preferably contain 85% by weight at the most of the
liquid crystal component C which comprises compounds having a
dielectric anisotropy of from -10 to 2. Preferred examples of the
liquid crystal compounds having a dielectric anisotropy of from -10
to 2 are as follows. That is, the liquid crystal compound has a
rod-shaped chemical structure in which its central part has a core
structure having 1 to 4 six-membered rings, six-membered rings
positioned at both termini of the central part in major axis
direction have terminal groups substituted at positions
corresponding to the major axis of the liquid crystal molecule and
both of the terminal groups positioned at both termini are
non-polar groups such as an alkyl group, an alkoxy group, an
alkoxyalkyl group, an alkenyl group, an alkenyloxy group and
alkanoyloxy group. The liquid crystal component C is constituted by
compounds within the range of preferably from 1 to 20 species, more
preferably from 2 to 12 species.
[0139] In view of such points, more desirable mode of the basic
structures of the compounds represented by general formulae (III-1)
to (III-4) is compounds represented by the general formulae
(III-1a) to (III-4o) described in the following. As the liquid
crystal component C of the present invention, it may contain
preferably from 10 to 100% by weight of compounds selected from the
compounds represented by the general formulae (III-1) to (III-4).
The liquid crystal component C which contains these compounds can
be thoroughly mixed with the liquid crystal component A which
contains compounds of the general formulae (I-1) to (I-3), is
useful in improving nematic phase at a low temperature, can adjust
the birefringence to desired level and is excellent in improving
sharpness and response of TN-LCD, TFT-LCD, PDLC, PN-LCD and the
like devices or temperature characteristics thereof. 9
[0140] Also, more preferred mode of the formulae (III-51) to
(III-58) of the side chain groups R.sup.31 to R.sup.38 is compounds
represented by the following general formulae (III-5a) to
(III-5bf).
3 (III-51) R.sup.31-- (III-52) R.sup.32-- (III-53) R.sup.33--
(III-54) R.sup.34-- (III-55) R.sup.35-- (III-56) R.sup.36--
(III-57) R.sup.37-- (III-58) R.sup.38-- (III-5a) CH.sub.3--
(III-5b) C.sub.2H.sub.5-- (III-5c) C.sub.3H.sub.7-- (III-5d)
C.sub.4H.sub.9-- (III-5e) C.sub.5H.sub.11-- (III-5f)
C.sub.6H.sub.13-- (III-5g) C.sub.7H.sub.15-- (III-5h) CH.sub.3O--
(III-5i) C.sub.2H.sub.5O-- (III-5j) C.sub.3H.sub.7O-- (III-5k)
C.sub.4H.sub.9O-- (III-5l) C.sub.5H.sub.11O-- (III-5m)
C.sub.6H.sub.13O-- (III-5n) C.sub.7H.sub.15O-- (III-5o)
CH.sub.3COO-- (III-5p) C.sub.2H.sub.5COO-- (III-5q)
C.sub.3H.sub.7COO-- (III-5r) C.sub.4H.sub.9COO-- (III-5s)
C.sub.5H.sub.11COO-- (III-5t) C.sub.6H.sub.13COO-- (III-5u)
C.sub.7H.sub.15COO-- (III-5v) CH.sub.3OCH.sub.2-- (III-5w)
CH.sub.3OC.sub.2H.sub.4-- (III-5x) CH.sub.3OC.sub.3H.sub.6--
(III-5y) CH.sub.3OC.sub.4H.sub.8-- (III-5z)
CH.sub.3OC.sub.5H.sub.10-- (III-5aa) C.sub.2H.sub.5OCH.sub.2--
(III-5ab) C.sub.2H.sub.5OC.sub.2H.sub.4- -- (III-5ac)
C.sub.2H.sub.5OC.sub.3H.sub.6-- (III-5ad)
C.sub.2H.sub.5OC.sub.4H.sub.8-- (III-5ae) C.sub.2H.sub.5OC.sub.5H-
.sub.10-- (III-5af) C.sub.3H.sub.7OCH.sub.2-- (III-5ag)
C.sub.3H.sub.7OC.sub.2H.sub.4-- (III-5ah) C.sub.3H.sub.7OC.sub.3H-
.sub.6-- (III-5ai) C.sub.3H.sub.7OC.sub.4H.sub.8-- (III-5aj)
C.sub.3H.sub.7OC.sub.5H.sub.10-- (III-5ak) CH.sub.2.dbd.CH--
(III-5al) CH.sub.3CH.dbd.CH-- (III-5am) C.sub.2H.sub.5CH.dbd.CH--
(III-5an) C.sub.3H.sub.7CH.dbd.CH-- (III-5ao)
CH.sub.2.dbd.CHC.sub.2H.sub.4-- (III-5ap)
CH.sub.3CH.sub.2.dbd.CHC.sub.2H.sub.4-- (III-5aq)
CH.sub.2.dbd.CHC.sub.2H.sub.5CH.dbd.CH-- (III-5ar)
CH.sub.2.dbd.CHO-- (III-5as) CH.sub.3CH.dbd.CHO-- (III-5at)
C.sub.2H.sub.5CH.dbd.CHO-- (III-5au) C.sub.3H.sub.7CH.dbd.CHO--
(III-5av) CH.sub.2.dbd.CHC.sub.2H.sub.- 4O-- (III-5aw)
CH.sub.3CH.sub.2.dbd.CHC.sub.2H.sub.4O-- (III-5ax)
CH.sub.2.dbd.CHC.sub.2H.sub.5CH.dbd.CHO-- (III-5ay) CHF.dbd.CH--
(III-5az) CH.sub.2.dbd.CF-- (III-5ba) CF.sub.2.dbd.CH-- (III-5bb)
CHF.dbd.CF-- (III-5bc) CHF.dbd.CHC.sub.2H.sub.4-- (III-5bd)
CH.sub.2.dbd.CFC.sub.2H.sub.- 4-- (III-5be)
CF.sub.2.dbd.CHC.sub.2H.sub.4-- (III-5bf)
CHF.dbd.CFC.sub.2H.sub.4--
[0141] In this connection, each of the compounds used in the
following was thoroughly purified by removing impurities using
distillation, column purification, recrystallization and the like
techniques.
[0142] Though the liquid crystal component C can contain compounds
represented by the aforementioned general formulae (III-1) to
(III-4), it may be composed of compounds represented by the
aforementioned general formulae (III-1), compounds represented by
the aforementioned general formulae (III-2), compounds represented
by the aforementioned general formulae (III-4) or compounds
represented by the aforementioned general formulae (III-3), or
these compounds may be used jointly. More preferred is a nematic
liquid crystal composition which contains the liquid crystal
component C that contains one or two or more compounds selected
from the compounds represented by the aforementioned general
formulae (III-1) to (III-3), wherein the total content of said
compounds is from 10 to 100% by weight.
[0143] In describing further in detail, if a general-purpose liquid
crystal composition is expected, it is desirable to use the
following compounds in the liquid crystal component C, and the
effects of the present invention can be obtained when such a type
of liquid crystal component C is used in combination with the
liquid crystal component A or, if used, the liquid crystal
component B.
[0144] Among compounds of the aforementioned general formulae
(III-1) to (III-4)
[0145] (III-ai): compounds in which R.sup.31 to R.sup.34 are an
alkenyl group having 2 to 5 carbon atoms, illustratively, compounds
having basic structures of general formulae (III-1a) to (III-4o) in
which the side chain groups R.sup.35 to R.sup.38 are (III-5a) to
(II-5bf) and the side chain groups R.sup.31 to R.sup.34 are
(III-5ak) to (II-5ap), (III-5ar) to (III-5aw) and (III-5ay) to
(III-5bf), by which more improved electro-optical characteristics
of STN-LCD, TFT-LCD, PDLC, PN-LCD and the like devices can be
obtained through the improvement of response property by reducing
viscosity and viscoelasticity and through the improvement of
nematic phase-isotropic liquid phase transition temperature,
and
[0146] (III-aii): compounds in which R.sup.35 to R.sup.38 are a
straight chain alkenyl or alkenyloxy group having 2 to 7 carbon
atoms, illustratively, compounds having basic structures of general
formulae (III-1a) to (III-4o) in which the side chain groups
R.sup.31 to R.sup.34 are (III-5a) to (II-5bf) and the side chain
groups R.sup.35 to R.sup.38 are (III-5ak) to (III-5bf), by which
response property can be improved through the reduction of
viscosity and viscoelasticity and the nematic phase-isotropic
liquid phase transition temperature can be improved, so that more
improved electro-optical characteristics of STN-LCD, TFT-LCD, PDLC,
PN-LCD and the like devices can be obtained.
[0147] Among compounds of the aforementioned general formula
(III-1),
[0148] (III-aiii): compounds in which k.sup.31 is 0 and Z.sup.32 is
a single bond or --(CH.sub.2).sub.2--, illustratively, compounds
having basic structures of general formulae (III-1a) and (III-1c)
in which the side chain groups are (III-5a) to (III-5bf), and
[0149] (III-aiv): compounds in which k.sup.31 is 1, illustratively,
compounds having basic structures of general formulae (III-1d) to
(III-1r) in which the side chain groups are (III-5a) to
(III-5bf).
[0150] (III-av): Compounds represented by the aforementioned
general formula (III-2), illustratively, compounds having basic
structures of general formulae (III-2a) to (III-2o) in which the
side chain groups are (III-5a) to (III-5bf).
[0151] Among compounds of the aforementioned general formula
(III-3),
[0152] (III-avi): compounds in which at least one of Y.sup.34,
Y.sup.35 and W.sup.34 to W.sup.36 is F and/or Y.sup.33 is F or
--CH.sub.3, illustratively, compounds having basic structures of
general formulae (III-3b), (III-3c), (III-3e) to (III-3g), (III-3i)
to (III-3o), (III-3r) to (III-3w), (III-3y) to (III-3ab), (III-3ad)
to (III-3aj), (III-3al) to (III-3as), (III-3au) to (III-3bb),
(III-3bk) to (III-3bs), (III-3bu), (III-3bv), (III-3by) to
(III-3ch) and (III-3ck) to (III-3dc) in which the side chain groups
are (III-5a) to (III-5bf),
[0153] (III-avii): compounds in which k.sup.33 is 0 and Z.sup.36 is
a single bond, illustratively, compounds having basic structures of
general formulae (III-3a) to (III-3c) in which the side chain
groups are (III-5a) to (III-5bf),
[0154] (III-aviii): compounds in which k.sup.33 is 0 and Z.sup.35
is a single bond, --OCO--, --CH.sub.2O--, --OCH.sub.2--,
--(CH.sub.2).sub.2--, --(CH.sub.2).sub.4--,
--CH.dbd.CH--(CH.sub.2).sub.2--, --(CH.sub.2).sub.2--CH.dbd.CH--,
--CH.dbd.N--, --CH.dbd.N--N.dbd.CH--, --N(O).dbd.N--, --CH.dbd.CH--
or --CF.dbd.CF--, illustratively, compounds having basic structures
of general formulae (III-3q) to (III-3w), (III-3ac) to (III-3bc),
(III-3be), (III-3bg), (III-3bi) to (III-3bs), (III-3bw), (III-3ci)
to (III-3dc), (III-3de) and (III-3dh) in, which the side chain
groups are (III-5a) to (III-5bf), and
[0155] (III-aix): compounds in which Z.sup.35 is --COO-- or
--C.ident.C-- and Z.sup.36 is --OCO--, --CH.sub.2O--,
--OCH.sub.2--, --(CH.sub.2).sub.2--, --(CH.sub.2).sub.4--,
--CH.dbd.CH--(CH.sub.2).sub.2- --, --(CH.sub.2).sub.2--CH.dbd.CH--,
--CH.dbd.N--, --CH.dbd.N--N.dbd.CH--, --N(O).dbd.N--,
--CH.dbd.CH--, --CF.dbd.CF-- or --C.ident.C--, illustratively,
compounds having basic structures of general formulae (III-3bf),
(III-3bh), (III-3df) and (III-3dg) in which the side chain groups
are (III-5a) to (III-5bf).
[0156] (III-ax): Compounds represented by the aforementioned
general formula (III-4), illustratively, compounds having basic
structures of general formulae (III-4a) to (III-4o) in which the
side chain groups are (III-5a) to (III-5bf).
[0157] (III-axi): Compounds represented by the aforementioned
general formulae (III-1) to (III-4) in which rings A.sup.31 to
A.sup.35 are trans-1,4-cyclohexylene, and hydrogen atoms in the
rings are replaced by deuterium atoms, illustratively, compounds
having basic structures of general formulae (III-1a) to (III-2o),
(III-3q) to (III-3bi), (III-4c), (III-4d) and (III-4h) in which the
side chain groups are (III-5a) to (III-5bf).
[0158] A nematic liquid crystal composition which contains one or
two or more compounds selected from the compounds represented by
these subgroups (III-ai) to (III-axi) is desirable.
[0159] Preferred mode of the compounds represented by the general
formulae (III-1) to (III-4) is a liquid crystal component C which
contains the following compounds.
[0160] Among compounds of the aforementioned general formula
(III-1) in which R.sup.31 is an alkyl group having 1 to 5 carbon
atoms or an alkenyl group having 2 to 5 carbon atoms and R.sup.35
is an alkyl or alkoxy group having 1 to 5 carbon atoms or an
alkenyl or alkenyloxy group having 2 to 5 carbon atoms,
[0161] (III-bi): compounds in which k.sup.31 is 0 and Z.sup.32 is a
single bond, --COO-- or --(CH.sub.2).sub.2--, illustratively,
compounds having basic structures of general formulae (III-1a) to
(III-1c) in which the side chain group R.sup.31 is compounds of
(III-5a) to (III-5e) and (III-5ak) to (III-5ap) and the side chain
group R.sup.35 is compounds of (III-5a) to (III-5e), (III-5g) to
(III-5l), (III-5ak) to (III-5ap), (III-5ar) to (III-5aw) and
(III-5ay) to (III-5bf), and
[0162] (III-bii): compounds in which k.sup.31 is 1, the ring
A.sup.31 is trans-1,4-cyclohexylene and one of Z.sup.31 and
Z.sup.32 is a single bond and the other is a single bond, --COO--
or --(CH.sub.2).sub.2--, illustratively, compounds having basic
structures of general formulae (III-1d) and (III-1g) to (III-1j) in
which the side chain group R.sup.31 is compounds of (III-5a) to
(III-5e) and (III-5ak) to (III-5ap) and the side chain group
R.sup.35 is compounds of (III-5a) to (III-5e), (III-5g) to
(III-5l), (III-5ak) to (III-5ap), (III-5ar) to (III-5aw) and
(III-5ay) to (III-5bf).
[0163] Among compounds of the aforementioned general formula
(III-2) in which R.sup.32 is an alkyl group having 1 to 5 carbon
atoms or an alkenyl group having 2 to 5 carbon atoms, R.sup.35 is
an alkyl or alkoxy group having 1 to 5 carbon atoms or an alkenyl
or alkenyloxy group having 2 to 5 carbon atoms and the ring
A.sup.32 is trans-1,4-cyclohexylene or
trans-1,4-cyclohexenylene,
[0164] (III-biii): compounds in which k.sup.32 is 0 and Z.sup.33 is
a single bond, --COO-- or --(CH.sub.2).sub.2--, illustratively,
compounds having basic structures of general formulae (III-2a),
(III-2d) and (III-2e) in which the side chain group R.sup.32 is
compounds of (III-5a) to (III-5e) and (III-5ak) to (III-5ap) and
the side chain group R.sup.36 is compounds of (III-5a) to (III-5e),
(III-5g) to (III-5l), (III-5ak) to (III-5ap), (III-5ar) to
(III-5aw) and (III-5ay) to (III-5bf), and
[0165] (III-biv): compounds in which k.sup.32 is 1 and one of
Z.sup.33 and Z.sup.34 is a single bond, illustratively, compounds
having basic structures of general formulae (III-2f) to (III-2i) in
which the side chain group R.sup.32 is compounds of (III-5a) to
(III-5e) and (III-5ak) to (III-5ap) and the side chain group
R.sup.36 is compounds of (III-5a) to (III-5e), (III-5g) to
(III-5l), (III-5ak) to (III-5ap), (III-5ar) to (III-5aw) and
(III-5ay) to (III-5bf).
[0166] Among compounds of the aforementioned general formula
(III-3) in which R.sup.33 is an alkyl group having 1 to 5 carbon
atoms or an alkenyl group having 2 to 5 carbon atoms and R.sup.37
is an alkyl or alkoxy group having 1 to 5 carbon atoms or an
alkenyl or alkenyloxy group having 2 to 5 carbon atoms,
[0167] (III-bv): compounds in which k.sup.33 is 0 and Z.sup.36 is a
single bond, --C.ident.C-- or --CH.dbd.N--N.dbd.CH--,
illustratively, compounds having basic structures of general
formulae (III-3a) to (III-3c) and (III-3h) to (III-3p) in which the
side chain group R.sup.33 is compounds of (III-5a) to (III-5e) and
(III-5ak) to (III-5ap) and the side chain group R.sup.37 is
compounds of (III-5a) to (III-5e), (III-5g) to (III-5l), (III-5ak)
to (III-5ap), (III-5ar) to (III-5aw) and (III-5ay) to
(III-5bf),
[0168] (III-bvi): compounds in which k.sup.33 is 1, Z.sup.35 is a
single bond, --(CH.sub.2).sub.2--, --COO-- or --C.ident.C-- and
Z.sup.36 is a single bond, --COO-- or --C.ident.C--,
illustratively, compounds having basic structures of general
formulae (III-3q) to (III-3bb), (III-3bd) to (III-3bg), (III-3bj)
to (III-3ch) and (III-3cj) to (III-3di) in which the side chain
group R.sup.33 is compounds of (III-5a) to (III-5e) and (III-5ak)
to (III-5ap) and the side chain group R.sup.37 is compounds of
(III-5a) to (III-5e), (III-5g) to (III-5l), (III-5ak) to (III-5ap),
(III-5ar) to (III-5aw) and (III-5ay) to (III-5bf),
[0169] (III-bvii) compounds in which one of Z.sup.35 and Z.sup.36
is a single bond and the other is a single bond or --C.ident.C--
and at least one of W.sup.34 and W.sup.35 is F, illustratively,
compounds having basic structures of general formulae (III-3r),
(III-3t), (III-3au), (III-3aw), (III-3ay), (III-3bk), (III-3bn),
(III-3bo), (III-3bz), (III-3cb), (III-3ce), (III-3cf), (III-3cu),
(III-3cx) and (III-3cz), in which the side chain group R.sup.33 is
compounds of (III-5a) to (III-5e) and (III-5ak) to (III-5ap) and
the side chain group R.sup.37 is compounds of (III-5a) to (III-5e),
(III-5g) to (III-5l), (III-5ak) to (III-5ap), (III-5ar) to
(III-5aw) and (III-5ay) to (III-5bf), and
[0170] (III-bviii): compounds in which either of Y.sup.35 and
Y.sup.36 is a compound substituted by F or CH.sub.3,
illustratively, compounds having basic structures of general
formulae (III-3c), (III-3f), (III-3g), (III-3j), (III-3l) to
(III-3o), (III-3s), (III-3u) to (III-3w), (III-3z), (III-3ab),
(III-3ae), (III-3ag), (III-3ai), (III-3aj), (III-3am), (III-3ao),
(III-3aq) to (III-3as), (III-3av), (III-3ax), (III-3az) to
(III-3bb), (III-3bl), (III-3bm), (III-3bp) to (III-3bs), (III-3bv),
(III-3ca), (III-3cc), (III-3cd), (III-3cg), (III-3ch), (III-3cm) to
(III-3cs), (III-3cv) to (III-3cx), (III-3da) to (III-3dc) in which
the side chain group R.sup.33 is compounds of (III-5a) to (III-5e)
and (III-5ak) to (III-5ap) and the side chain group R.sup.37 is
compounds of (III-5a) to (III-5e), (III-5g) to (III-5l), (III-5ak)
to (III-5ap), (III-5ar) to (III-5aw) and (III-5ay) to
(III-5bf).
[0171] (III-bix): Compounds of the aforementioned general formula
(III-4) in which R.sup.34 is an alkyl group having 1 to 5 carbon
atoms or an alkenyl group having 2 to 5 carbon atoms, R.sup.38 is
an alkyl or alkoxy group having 1 to 5 carbon atoms or an alkenyl
or alkenyloxy group having 2 to 5 carbon atoms and
k.sup.34+k.sup.35 is 0, illustratively, compounds having basic
structures of general formulae (III-4a) and (III-4b) in which the
side chain group R.sup.34 is compounds of (III-5a) to (III-5e) and
(III-5ak) to (III-5ap) and the side chain group R.sup.38 is
compounds of (III-5a) to (III-5e), (III-5g) to (III-5l), (III-5ak)
to (III-5ap), (III-5ar) to (III-5aw) and (III-5ay) to
(III-5bf).
[0172] A nematic liquid crystal composition which contains one or
two or more compounds selected from the compounds represented by
these subgroups (III-bi) to (III-bix), wherein the total content of
these compounds is from 10 to 100% by weight as the liquid crystal
component C, is desirable.
[0173] Particularly preferred mode of the compounds represented by
general formulae (III-1) to (III-4) is a liquid crystal component C
which contains the following compounds.
[0174] Inclusion of the compounds of general formulae (III-1) to
(III-4) as a liquid crystal component C exerts characteristic
effects in that viscosity and viscoelasticity can be reduced and
specific resistance and voltage holding ratio become relatively
high. It is desirable that viscosity of the liquid crystal
component C is as low as possible and, in the case of the present
invention, the viscosity is preferably 45 cp or less, more
preferably 30 cp or less, most preferably 20 cp or less and
particularly preferably 15 cp or less. From such a point of view,
more preferred compounds are,
[0175] (III-ci): compounds having basic structures of (III-1a) to
(III-1f), (III-1k), (III-2a) to (III-2f), (III-3a), (III-3h) to
(III-3j), (III-3o), (III-3p), (III-3q), (III-3ac), (III-3at) to
(III-3ax), (III-3ba), (III-3bb), (III-3bf), (III-3bg), (III-3bx) to
(III-3cb) and (III-3ct) to (III-3cx), more preferably,
[0176] (III-cii): compounds of the aforementioned (III-ci) in which
R.sup.31 to R.sup.34 are a straight chain alkyl group having 2 to 5
carbon atoms or an alkenyl group of
CH.sub.2.dbd.CH--(CH.sub.2).sub.q (q=0 or 2) and R.sup.35 to
R.sup.38 are a straight chain alkyl group having 1 to 5 carbon
atoms or an alkenyl group of CH.sub.2.dbd.CH--(CH.su- b.2).sub.q
(q=0 or 2), most preferably
[0177] (III-ciii): compounds having basic structures of (III-1a),
(III-1d), (III-2a), (III-2f), (III-3a), (III-3h), (III-3p) and
(III-3q), in which both side chain groups are alkenyl groups.
[0178] Though the liquid crystal component C of the present
invention can be constructed solely with any one of the compounds
represented by the general formula (III-1), general formula
(III-2), general formula (III-3) and general formula (III-4), the
birefringence of the liquid crystal composition can be optimized
easily in response to its use, by jointly using
[0179] (III-civ): compounds represented by the general formula
(III-1) and/or general formula (III-2), particularly compounds of
general formulae (III-1a), (III-1d), (III-2a) to (III-2c) and
(III-2f) and
[0180] (III-cv): compounds represented by the general formula
(III-3) and/or general formula (III-4), particularly those
compounds in which Z.sup.35 is a single bond, --C.ident.C-- or
--CH.dbd.N--N.dbd.CH--, illustratively, compounds of general
formulae (III-3a), (III-3h), (III-3p), (III-3q), (III-3at),
(III-4a) and (III-4h). For general purpose use, the birefringence
can be reduced, and reduction of non-uniformity of color on liquid
crystal display systems, improvement of viewing angle
characteristics and increment of contrast ratio can be achieved
easily, by frequently using compounds of general formula (III-1)
and general formula (III-2), such as compounds of general formulae
(III-1a) to (III-2f). Also, when compounds of the general formula
(III-3) such as compounds of general formulae (III-3a) to (III-3j)
or of the general formula (III-4) such as compounds of general
formulae (III-4a) to (III-4e) are used frequently, the
birefringence can be increased and preparation of a liquid crystal
display device having a thin liquid crystal layer of from 1 to 5
.mu.m becomes possible.
[0181] A liquid crystal component C which contains these compounds
of (III-ai) to (III-cv) has a feature in that it can mix thoroughly
with the essential component, liquid crystal component A, and is
useful in controlling the birefringence, improving sharpness or
temperature-dependency thereof or improving response property
depending on each purpose. These compounds are excellent in at
least one of such effects, and these effects can be obtained even
by a small content of from 0.1 to 30% by weight based on the total
amount of the nematic liquid crystal composition of the present
invention.
[0182] In the compounds of the present invention, the composing
atoms can be replaced by their corresponding isotopic atoms
consciously. In that case, compounds in which hydrogen atoms are
replaced by deuterium atoms are particularly desirable, because
they exert more desirable effects on miscibility, elastic constant,
pre-tilt angle, voltage holding ratio and the like factors.
Preferred are compounds in which hydrogen atoms existing in the
aforementioned side chain groups, linking groups or rings are
replaced by deuterium atoms. More preferably, the side chain groups
are substituted or unsubstituted alkyl groups and alkenyl groups,
the rings are substituted or unsubstituted 1,4-phenylene,
pyrimidine-2,5-diyl, trans-1,4-cyclohexylene,
trans-1,4-cyclohexenylene and trans-1,4-dioxane-2,5-diyl and the
linking groups are --CH.sub.2O--, --OCH.sub.2--,
--(CH.sub.2).sub.2--, --(CH.sub.2).sub.4--,
--CH.dbd.CH--(CH.sub.2).sub.2--, --(CH.sub.2).sub.2--CH.dbd.CH--,
--CH.dbd.N-- and --CH.dbd.N--N.dbd.CH--. Particularly preferred are
alkyl groups, alkenyl groups, 1,4-phenylene,
trans-1,4-cyclohexylene, --(CH.sub.2).sub.2-- and
--(CH.sub.2).sub.413 .
[0183] Currently, polyimide-based orientation films such as LX1400,
SE150, SE610, AL1051 and AL3408 are frequently used in TN-LCD,
STN-LCD or TFT-LCD. Liquid crystal display characteristics, display
quality, reliability and productivity are deeply related to the
specification of orientation films, and pre-tilt angle
characteristics for example are important for liquid crystal
materials. In order to obtain desired liquid crystal display
characteristics and uniform orientation, it is necessary to adjust
the size of pre-tilt angle as occasion demands. For example, the
orientation becomes unstable in the case of a large pre-tilt angle,
and sufficient display characteristics cannot be obtained when the
angle is small.
[0184] The present inventors have found that liquid crystal
materials having larger pre-tilt angle and liquid crystal materials
having smaller angle can be sorted out and that desired liquid
crystal display characteristics and uniform orientation can be
obtained from liquid crystal materials by the application of this
finding. This technique can be applied to the present invention.
For example, a case in which the liquid crystal component B
contains compounds of the general formulae (II-1) to (II-4) is as
follows. More larger pre-tilt angle can be obtained by increasing
the content of compounds in which R.sup.21 is an alkenyl group,
X.sup.21 is F, Cl or --CN and Y.sup.21 and Y.sup.22 are F and/or
compounds in which R.sup.21 is an alkyl group, X.sup.21 is F, Cl or
--CN and Z.sup.22 is --C.sub.2H.sub.4-- or --C.sub.4H.sub.8--, and
more smaller pre-tilt angle can be obtained by increasing the
content of compounds in which R.sup.21 is an alkenyl group or
C.sub.sH.sub.2s+1--O--C.sub.tH.sub.2t, X.sup.21 is F, Y.sup.21 is F
and Y.sup.22 is H and/or compounds in which Z.sup.22 is --COO--.
Illustratively, in the case of compounds in which rings A.sup.21 to
A.sup.24 in the general formulae (II-1), (II-2) and (II-4) and
rings A.sup.31 to A.sup.35 in the general formulae (III-1) to
(III-4) are cyclohexane rings and hydrogen atoms of said rings are
replaced by deuterium atoms, the pre-tilt angle varies depending on
the replaced positions and can therefore be controlled within wide
range.
[0185] Also, frequent use of compounds in which hydrogen atoms are
replaced by deuterium atoms exerts special effect to maintain
further high voltage holding ratio and therefore is desirable in
terms of the display characteristics and production yield of
TFT-LCD, PDLC, PN-LCD and the like devices for active use. The
reason for such an effect may be that properties of heavy water,
namely differences in equilibrium constant and rate constant of the
reaction, low ionic mobility, low solubility of inorganic
substances and oxygen and the like properties, are also expressed
in the liquid crystal compounds. In order to maintain more higher
voltage holding ratio, it can mostly be achieved by including 10 to
40% by weight or more larger amount of the aforementioned compounds
based on the total amount of the liquid crystal composition.
[0186] The content of each liquid crystal component in the nematic
liquid crystal composition of the present invention is as follows.
The content of the liquid crystal component A is within the range
of from 5 to 70% by weight, preferably within the range of from 5
to 60% by weight, more preferably within the range of from 5 to 50%
by weight. The content of the liquid crystal component B is within
the range of from 0 to 95% by weight, preferably within the range
of from 3 to 80% by weight, more preferably within the range of
from 5 to 60% by weight. The content of the liquid crystal
component C is up to 95% by weight at the most, preferably within
the range of from 3 to 70% by weight, more preferably within the
range of from 5 to 70% by weight. The content of compounds
represented by the general formulae (I-1) to (I-18) is preferably
10% by weight or less as a single compound, and it is desirable
that more larger content is composed of two or more compounds. The
content of compounds represented by the general formulae (II-1) to
(II-4), illustratively compounds represented by the general
formulae (II-1a) to (II-4g), is preferably 30% by weight or less,
more preferably 25% by weight or less, as a single compound, and it
is desirable that more larger content is composed of two or more
compounds, and their content in the liquid crystal component B is
within the range of from 10 to 100% by weight, preferably within
the range of from 50 to 100% by weight, more preferably within the
range of from 75 to 100% by weight. The content of compounds
represented by the general formulae (III-1) to (III-4),
illustratively compounds represented by the general formulae
(III-1a) to (III-4o), is preferably 30% by weight or less, more
preferably 25% by weight or less, as a single compound, and it is
desirable that more larger content is composed of two or more
compounds, and their content in the liquid crystal component C is
within the range of from 10 to 100% by weight, preferably within
the range of from 50 to 100% by weight, more preferably within the
range of from 75 to 100% by weight.
[0187] In order to improve characteristics of the liquid crystal
composition of the present invention, the composition may further
contain usually used nematic liquid crystals, smectic liquid
crystals, cholesteric liquid crystals and the like liquid crystal
compounds, in addition to the aforementioned compounds represented
by general formulae (I-1) to (III-4). For example, one or a
plurality of compounds having a core structure composed of 4
six-membered rings and having a liquid crystal phase-isotropic
liquid phase transition temperature of 100.degree. C. or more can
be included. However, since the use of such compounds in a large
amount reduces characteristics of the nematic liquid crystal
composition, the amount is limited in response to the required
characteristics of the nematic liquid crystal composition.
[0188] The crystal phase- or smectic phase-nematic phase transition
temperature is preferably -10.degree. C. or less, more preferably
-20.degree. C. or less, most preferably -30.degree. C. or less. The
nematic phase-isotropic liquid phase transition temperature is
preferably 50.degree. C. or more, more preferably 70.degree. C. or
more, most preferably within the range of from 80.degree. C. to
150.degree. C. The liquid crystal composition of the present
invention may have a dielectric anisotropy of 3 or more but
preferably within the range of from 4 to 40, and a range of from 4
to 16 is desirable when quick response is important or a range of
from 17 to 30 is desirable when more lower driving voltage is
required. Smaller or medium birefringence is within the range of
preferably from 0.08 to 0.195, more preferably from 0.10 to 0.18.
The nematic liquid crystal composition having such characteristics
is effective for use in twisted nematic or super twisted nematic
liquid crystal display devices.
[0189] When more quicker response is desired for the size of
driving voltage, the liquid crystal composition of the present
invention can be controlled as follows. When medium degree of
driving voltage is desired, the liquid crystal composition of the
present invention may preferably have a dielectric anisotropy
within the range of from 3 to 15 and a viscosity within the range
of from 8 to 20 c.p. at 20.degree. C. In that case, viscosity of
the liquid crystal component C alone is preferably 25 c.p. or less,
more preferably 15 c.p. or less, most preferably 10 c.p. or less.
Also, when particularly low driving voltage is desired, the liquid
crystal composition of the present invention may have a dielectric
anisotropy within the range of preferably from 15 to 30, more
preferably from 18 to 28.
[0190] The aforementioned nematic liquid crystal composition is
useful in quick response TN-LCD and STN-LCD and also in liquid
crystal display devices in which color display can be made by
birefringence of liquid crystal phase and retardation film without
using color filter layers and can be used in a transmission type or
reflection type liquid crystal display device. Since this liquid
crystal display device has substrates having transparent electrode
layers, in which at least one of them is transparent, molecules of
the aforementioned nematic liquid crystal composition can be
arranged between these substrates in a twisted orientation which
can be selected in response to each object within the range of from
30.degree. to 360.degree., preferably within the range of from
90.degree. to 270.degree., more preferably within the range of from
45.degree. to 135.degree. or within the range of from 180.degree.
to 260.degree.. Because of this, the liquid crystal composition of
the present invention can contain a compound having an optically
active group which shows an induced helical pitch of from 0.5 to
1,000 .mu.m. Examples of such a compound include cholesterol
derivatives, chiral nematic liquid crystals, ferroelectric liquid
crystals and the like, more illustratively, cholesterylnonanate,
C-15, CB-15, S-811 and the like may be used preferably. Also, it is
known that there are compounds whose induced helical pitch becomes
long and or short by the increment of temperature, and one or a
plurality of compounds of one of such types may be used or one or a
plurality of compounds of both types may also be used. Their amount
to be mixed is preferably within the range of from 0.001% by weight
to 10% by weight, more preferably within the range of from 0.05% by
weight to 3% by weight. Most preferably within the range of from
0.1% by weight to 3% by weight. As a matter of course, however,
these amounts are selected to obtain a desired induced helical
pitch by the helix angle .theta. and the thickness d between the
aforementioned substrates.
[0191] It is desirable to select the pre-tilt angle which is
obtained by the orientation film arranged on the transparent
electrode substrate within the range of from 1.degree. to
20.degree., and a pre-tilt angle of from 1.degree. to 4.degree. is
desirable when the helix angle is from 30.degree. to 100.degree., a
pre-tilt angle of from 2.degree. to 6.degree. is desirable when the
helix angle is from 100.degree. to 180.degree., a pre-tilt angle of
from 3.degree. to 12.degree. is desirable when the helix angle is
from 180.degree. to 260.degree. and a pre-tilt angle of from
6.degree. to 20.degree. is desirable when the helix angle is from
260.degree. to 360.degree..
[0192] The present invention also provides phenyl benzoate
derivatives represented by the general formula (I) and as
intermediates for use in the production thereof
2-fluoro-4-(3-alkenyl)benzoic acid represented by the general
formula (II). The group R represents a hydrogen atom or a straight
chain alkyl group having 1 to 7 carbon atoms, preferably a hydrogen
atom or methyl group. When R is an alkyl group, it is desirable
that configuration of the double bond is trans configuration. Each
of X, Y and Z is independently a fluorine atom or a hydrogen atom,
but it is desirable that at least one of X, Y and Z is a fluorine
atom, more preferably at least two of them are fluorine atoms, in
order to improve the threshold voltage reducing effect through the
increment of dielectric anisotropy. Also, since solubility and
liquid crystalline property are slightly reduced when all of X, Y
and Z are fluorine atoms, it is desirable that at least one of them
is a hydrogen atom. In consequence, it is most desirable that X is
a fluorine atom and Y is a hydrogen atom when Z is a fluorine atom
and that X and Y are both fluorine atoms when Z is a hydrogen
atom.
[0193] The following describes examples for production methods of
the phenyl benzoic acid derivatives of the present invention
represented by the general formula (I): 10
[0194] Namely, the derivative (I) can be obtained easily by
treating a fluorine-substituted 4-(3-alkenyl)benzoic acid
represented by the general formula (II) 11
[0195] (wherein R and Z are as defined in the foregoing) with
thionyl chloride or the like chlorination agent to convert it into
corresponding acid chloride which is then allowed to react with a
4-cyanophenol or a fluorine substitution product thereof
represented by the general formula (IV) 12
[0196] (wherein X and Y are as defined in the foregoing) in the
presence of pyridine or the like base. It can also be obtained by
allowing the compound (II) to react directly, without converting it
into acid chloride, with the compound (IV) in the presence of
dicyclohexylcarbodiimide (DCC) or the like condensing agent.
[0197] In this connection, the fluorine-substituted
4-(3-alkenyl)benzoic acid of formula (II) can be produced in the
following manner in response to its group Z.
[0198] (a) When Z is a fluorine atom,
[0199] 1) a Grignard reagent prepared from
3,5-difluoro-1-bromobenzene (Va) 13
[0200] or a phenyllithium reagent is allowed to react with
N,N-dimethylformamide (DMF) or the like formylation agent and then
treated with sodium borohydride or the like reducing agent to
obtain 3,5-difluorobenzyl alcohol (VIa): 14
[0201] Alternatively, the compound (VIa) can also be obtained with
one step by allowing the Grignard reagent or phenyllithium reagent
to react with formaldehyde in stead of the formylation agent. By
allowing 3,5-difluorobenzyl bromide (VIIa) 15
[0202] obtained by bromination of the compound (VIa) to react with
a Grignard reagent represented by the general formula (VIIIa):
16
[0203] (wherein R is as defined in the foregoing, and W is chlorine
or bromine atom), a 3,5-difluoro-1-(3-alkenyl)benzene represented
by the general formula (IXa) 17
[0204] (wherein R is as defined in the foregoing) is obtained.
Alternatively, the compound (IXa) can also be obtained by carrying
out the reaction with a Grignard reagent represented by the general
formula (VIIIb) 18
[0205] (wherein R is as defined in the foregoing, and W is chlorine
or bromine atom), in stead of the reagent (VIIIa), and then
trans-reducing the resulting triple bond by alkali metal such as
sodium or lithium in liquid ammonia or a lower amine, and the
latter case is desirable when R is an alkyl group. By treating this
with butyl lithium or the like alkyl lithium and then allowing to
react with carbon dioxide, a 2,6-difluoro-4-(3-alkenyl)benzoic acid
(IIa) 19
[0206] (wherein R is as defined in the foregoing), which is a
member of the fluorine-substituted 4-(3-alkenyl)benzoic acid
represented by the general formula (II) in which Z is a fluorine
atom, can be obtained.
[0207] 2) Alternatively, by allowing the Grignard reagent or a
phenyllithium reagent prepared from the compound (Va) to react with
an unsaturated carboxylic acid derivative represented by the
general formula (X) 20
[0208] (wherein R is as defined in the foregoing, G is CN, COOR' or
COCl, and R' is a lower alkyl group having 1 to 4 carbon atoms) and
then hydrolyzing the reaction product as occasion demands, a
compound represented by the general formula (XIa) 21
[0209] (wherein R is as defined in the foregoing) is obtained. By
reducing the carbonyl group, the aforementioned compound of formula
(IXa) can be obtained.
[0210] (b) When Z is hydrogen atom,
[0211] 3) a Grignard reagent prepared from 3-fluoro-1-bromobenzene
(Vb) 22
[0212] or a phenyllithium reagent is allowed to react in the same
manner as described in (a)-1) and the subsequent reaction is
carried out in the same manner, thereby obtaining a compound
represented by the general formula (IXb) 23
[0213] (wherein R is as defined in the foregoing). By subjecting
this to acetylation and subsequent oxidation with a hypochlorite, a
2-fluoro-4-(3-alkenyl)benzoic acid (IIb) 24
[0214] (wherein R is as defined in the foregoing), which is a
member of the fluorine-substituted 4-(3-alkenyl)benzoic acid
represented by the general formula (II) in which Z is a hydrogen
atom, can be obtained.
[0215] 4) Alternatively, an acid chloride derived from the compound
(IIb) can be directly obtained by allowing the compound (IXb) to
react with oxalyl chloride in the presence of Lewis acid.
[0216] 5) Alternatively, using a compound (Vc) 25
[0217] (wherein P is 4,4-dimethyl-1,3-oxazolin-2-yl group or the
like carboxyl group-protecting group) which contains protected
carboxyl group, in stead of 3-fluoro-1-bromobenzene (Vb), a
compound represented by the general formula (XIIb) 26
[0218] (wherein R and P are as defined in the foregoing) can be
obtained in the same manner as described in the aforementioned step
2) or 3). The benzoic acid derivative of formula (IIb) can also be
obtained by removing this protecting group.
[0219] These fluorine-substituted 4-(3-alkenyl)benzoic acids and
2,6-difluoro-4-(3-alkenyl)benzoic acids of the general formula
(II), are novel compounds and markedly useful as production
intermediates of not only compounds (I) of the present invention
but also other various liquid crystal compounds, and the present
invention also provides these compounds of formula (II).
[0220] Typical examples of the compounds represented by the general
formula (I) thus produced by the aforementioned production methods
are shown in Table 1.
4TABLE 1 Phase transition temperature of the compounds of general
formula (I) Phase transition No. Compound temp. (I)-1 27 Cr 58.6 I
(I)-2 28 Cr 62.0 I (In the table, Cr means crystal phase and I
means isotropic liquid phase. The phase transfer temperature is
".degree. C.".)
[0221] The compound (I) of the present invention has a structural
feature in that it has 3-alkenyl groups as its side chain groups,
in stead of alkyl groups. A large number of compounds having
alkenyl groups as the side chains have been known, and it has been
reported that they have various characteristics in comparison with
similar compounds in which their corresponding side chains are
alkyl groups, but reports on the compounds in which 3-alkenyl
groups are directly bonded to the benzoic acid nucleus are
extremely scarce, and virtually nothing is known about a high P
type compound such as of the general formula (I-6) in which a
fluorine atom is introduced into the benzoic acid nucleus. The
compound of the present invention has rendered possible the
solution to the aforementioned problems by providing its structure
with such characteristics.
[0222] Also, as shown in Table 1, some of the compounds represented
by the general formula (I) do not show nematic liquid crystalline
properties by itself. However, dropping degree of the nematic
phase-isotropic liquid phase transition temperature (T.sub.N-1)
when they are added to the host liquid crystal composition is at
least the same as the case of the compound of general formula (I-6)
and not so large when compared with the compounds of group A1
having small number of substituted fluorine atoms. In addition,
since they have relatively low melting point and are excellent in
their miscibility with other liquid crystal compositions, a problem
of causing precipitation and the like is scarce. In consequence,
they can be used suitably in the form of their mixture with other
liquid crystal compounds, particularly as materials of TN type, STN
type and the like field-effect type display cells.
[0223] Typical examples of nematic liquid crystal compounds which
can be used by mixing with the compounds represented by the general
formula (I) include phenyl benzoate derivatives, phenyl
cyclohexanecarboxylate derivatives, biphenyl-4-yl
cyclohexanecarboxylate derivatives, phenyl
cyclohexanecarbonyloxybenzoate derivatives, phenyl
cyclohexylbenzoate derivatives, cyclohexyl cyclohexylbenzoate
derivatives, biphenyl derivatives, cyclohexylbenzene derivatives,
terphenyl derivatives, bicyclohexane derivatives,
4-cyclohexylbiphenyl derivatives, 4-phenylbicyclohexane
derivatives, tercyclohexane derivatives, 1,2-dicyclohexylethane
derivatives, 1,2-diphenylethane derivatives, 1,2-diphenylethine
derivatives, (2-cyclohexylethyl)benzene derivatives,
4-phenetylbicyclohexane derivatives, 4-(2-cyclohexylethyl)biphenyl
derivatives, 1-(4-phenyl)cyclohexyl-2-cyclohexylethane derivatives,
1-(4-cyclohexylphenyl)-2-phenylethine derivatives, phenylpyrimidine
derivatives, (4-biphenyl-4-yl)pyrimidine derivatives,
phenylpyridine derivatives, (4-biphenyl-4-yl)pyridine derivatives
and the like.
[0224] The liquid crystal composition of the present invention can
be obtained by including the liquid crystal components A, B and C
described in detail in the foregoing. Though nematic liquid crystal
compositions (1-01) to (1-16) are shown in the following as
preferred examples, the present invention is not restricted by
these examples. Among these examples, nematic liquid crystal
compositions (1-01) to (1-05) and (1-11) to (1-16) can be used in
TN-LCD, nematic liquid crystal compositions (1-06) to (1-09) can be
used in STN-LCD and nematic liquid crystal composition (1-16) can
be used in PDLC and PN-LCD. In addition, depending on each desired
object and use, one or a plurality of compounds (1-0101) to
(1-1610) represented by these examples can be replaced by certain
compounds of the general formulae (I-1) to (III-4), illustratively,
compounds having basic structures of general formulae (I-1) to
(I-18) in which their side chain groups are (I-a) to (I-bc),
compounds having basic structures of general formulae (II-1a) to
(II-4g) in which their side chain groups are (II-5a) to (II-5r) and
partial structures of the polar groups are general formulae (II-6a)
to (II-6r) and compounds having basic structures of general
formulae (III-1a) to (III-4o) in which their side chain groups are
(III-5a to (III-5bf). As preferred examples of the composition,
nematic liquid crystal compositions (1-01) to (1-16) are shown in
the following.
5 (% by weight) Nematic liquid crystal composition (1-01) (1-0101)
29 10 (1-0102) 30 10 (1-0103) 31 5 (1-0104) 32 5 (1-0105) 33 5
(1-0106) 34 5 (1-0107) 35 6 (1-0108) 36 6 (1-0109) 37 10 (1-0110)
38 8 (1-0111) 39 5 (1-0112) 40 5 (1-0113) 41 5 (1-0114) 42 5
(1-0115) 43 5 (1-0116) 44 5 Nematic liquid crystal composition
(1-02) (1-0201) 45 17 (1-0202) 46 12 (1-0203) 47 11 (1-0204) 48 5
(1-0205) 49 10 (1-0206) 50 10 (1-0207) 51 7 (1-0208) 52 8 (1-0209)
53 5 (1-0210) 54 5 (1-0211) 55 5 (1-0212) 56 5 Nematic liquid
crystal composition (1-03) (1-0301) 57 8 (1-0302) 58 10 (1-0303) 59
7 (1-0304) 60 12 (1-0305) 61 18 (1-0306) 62 10 (1-0307) 63 5
(1-0308) 64 5 (1-0309) 65 5 (1-0310) 66 5 (1-0311) 67 5 (1-0312) 68
5 (1-0313) 69 5 Nematic liquid crystal composition (1-04) (1-0401)
70 12 (1-0402) 71 12 (1-0403) 72 18 (1-0404) 73 6 (1-0405) 74 6
(1-0406) 75 5 (1-0407) 76 10 (1-0408) 77 12 (1-0409) 78 7 (1-0410)
79 7 (1-0411) 80 5 Nematic liquid crystal composition (1-05)
(1-0501) 81 8 (1-0502) 82 6 (1-0503) 83 7 (1-0504) 84 10 (1-0505)
85 11 (1-0506) 86 10 (1-0507) 87 10 (1-0508) 88 10 (1-0509) 89 9
(1-0510) 90 3 (1-0511) 91 3 (1-0512) 92 4 (1-0513) 93 3 (1-0514) 94
3 (1-0515) 95 3 Nematic liquid crystal composition (1-06) (1-0601)
96 12 (1-0602) 97 11 (1-0603) 98 7 (1-0604) 99 7 (1-0605) 100 11
(1-0606) 101 6 (1-0607) 102 5 (1-0608) 103 5 (1-0609) 104 5
(1-0610) 105 5 (1-0611) 106 5 (1-0612) 107 5 (1-0613) 108 5
(1-0614) 109 5 (1-0615) 110 3 (1-0616) 111 3 Nematic liquid crystal
composition (1-07) (1-0701) 112 10 (1-0702) 113 11 (1-0703) 114 4
(1-0704) 115 7 (1-0705) 116 12 (1-0706) 117 12 (1-0707) 118 5
(1-0708) 119 5 (1-0709) 120 7 (1-0710) 121 7 (1-0711) 122 4
(1-0712) 123 4 (1-0713) 124 4 (1-0714) 125 5 (1-0715) 126 3 Nematic
liquid crystal composition (1-08) (1-0801) 127 12 (1-0802) 128 12
(1-0803) 129 9 (1-0804) 130 8 (1-0805) 131 5 (1-0806) 132 9
(1-0807) 133 5 (1-0808) 134 5 (1-0809) 135 5 (1-0810) 136 6
(1-0811) 137 5 (1-0812) 138 4 (1-0813) 139 5 (1-0814) 140 5
(1-0815) 141 5 Nematic liquid crystal composition (1-09) (1-0901)
142 4 (1-0902) 143 3 (1-0903) 144 3 (1-0904) 145 3 (1-0905) 146 3
(1-0906) 147 3 (1-0907) 148 4 (1-0908) 149 18 (1-0909) 150 17
(1-0910) 151 17 (1-0911) 152 4 (1-0912) 153 7 (1-0913) 154 4
(1-0914) 155 5 (1-0915) 156 5 Nematic liquid crystal composition
(1-10) (1-1001) 157 10 (1-1002) 158 5 (1-1003) 159 5 (1-1004) 160 5
(1-1005) 161 5 (1-1006) 162 10 (1-1007) 163 10 (1-1008) 164 20
(1-1009) 165 10 (1-1010) 166 7 (1-1011) 167 3 (1-1012) 168 5
(1-1013) 169 5 Nematic liquid crystal composition (1-11) (1-1101)
170 7 (1-1102) 171 8 (1-1103) 172 5 (1-1104) 173 10 (1-1105) 174 20
(111-06) 175 10 (1-1107) 176 10 (1-1108) 177 10 (1-1109) 178 5
(1-1110) 179 10 (1-1111) 180 5
[0225] Characteristic values of the aforementioned nematic liquid
crystal composition (1-10) are shown in the following.
[0226] T.sub.N-I: 88.6.degree. C.
[0227] T.sub..fwdarw.N: -70.degree. C.
[0228] .DELTA..epsilon.: 8.6
[0229] .DELTA.n: 0.168
[0230] Threshold voltage when TN-LCD is constructed (Vth): 2.01 V
(8.mu.)
[0231] Sharpness when TN-LCD is constructed (.gamma.): 1.15
[0232] Threshold voltage when STN-LCD is constructed (Vth): 2.27
V
[0233] Sharpness when STN-LCD is constructed (.gamma.): 1.028
6 Nematic liquid crystal composition (1-12) (% by weight) (1-1201)
181 10 (1-1202) 182 7 (1-1203) 183 20 (1-1204) 184 20 (1-1205) 185
4 (1-1206) 186 4 (1-1207) 187 4 (1-1208) 188 4 (1-1209) 189 4
(1-1210) 190 5 (1-1211) 191 5 (1-1212) 192 5 (1-1213) 193 3
(1-1214) 194 5
[0234] Characteristic values of the aforementioned nematic liquid
crystal composition (1-11) are shown in the following.
[0235] T.sub.N-1: 70.1.degree. C.
[0236] T.sub..fwdarw.N: -70.degree. C.
[0237] .DELTA..epsilon.: 7.1
[0238] .DELTA.n: 0.084
[0239] Threshold voltage when TN-LCD is constructed (Vth): 1.66 V
(8.mu.)
[0240] Sharpness when TN-LCD is constructed (.gamma.): 1.17
7 (% by weight) Nematic liquid crystal composition (1-13) (1-1301)
195 10 (1-1302) 196 10 (1-1303) 197 10 (1-1304) 198 10 (1-1305) 199
10 (1-1306) 200 10 (1-1307) 201 10 (1-1308) 202 10 (1-1309) 203 10
(1-1310) 204 5 (1-1311) 205 5 Nematic liquid crystal composition
(1-14) (1-1401) 206 5 (1-1402) 207 10 (1-1403) 208 5 (1-1404) 209
10 (1-1405) 210 10 (1-1406) 211 10 (1-1407) 212 10 (1-1408) 213 10
(1-1409) 214 10 (1-1410) 215 10 (1-1411) 216 5 (1-1412) 217 5
[0241] 218
[0242] Characteristic values of the aforementioned nematic liquid
crystal composition (1-14) are shown in the following.
[0243] T.sub.N-1: 97.1.degree. C.
[0244] T.sub..fwdarw.N: -70.degree. C.
[0245] .DELTA..epsilon.: 7.6
[0246] .DELTA.n: 0.058
[0247] Threshold voltage when TN-LCD is constructed (Vth): 1.78 V
(8.mu.)
[0248] Sharpness when TN-LCD is constructed (.gamma.): 1.15
8 (% by weight) Nematic liquid crystal composition (1-15) (1-1501)
219 10 (1-1502) 220 10 (1-1503) 221 10 (1-1504) 222 5 (1-1505) 223
5 (1-1506) 224 15 (1-1507) 225 5 (1-1508) 226 10 (1-1509) 227 10
(1-1510) 228 10 (1-1511) 229 5 (1-1512) 230 5 Nematic liquid
crystal compositions (1-16) (1-1601) 231 10 (1-1602) 232 10
(1-1603) 233 13 (1-1604) 234 17 (1-1605) 235 10 (1-1606) 236 10
(1-1607) 237 10 (1-1608) 238 10 (1-1609) 239 5 (1-1610) 240 5
[0249] 241
[0250] Liquid crystal display systems are currently under a state
of severely heated price competition. In view of this, a problem to
be resolved for liquid crystal materials is how to optimize their
display characteristics for various applications simply and easily,
and systematized liquid crystal materials, such as a two bottle
system comprising two types of liquid crystal materials or a four
two bottle system comprising four types of liquid crystal
materials, are expected. The typical characteristics are threshold
voltage, birefringence and nematic phase-isotropic liquid phase
transition temperature. For example, when a two bottle system which
comprises a liquid crystal material having a high threshold voltage
and a liquid crystal material having a low threshold voltage, but
the other characteristics are equivalent, is used, quicker and more
inexpensive results can be achieved by optionally formulating these
two liquid crystal materials without restriction by driving
electronic parts and the like to be used. The present invention is
also useful from such a point of view, and compositions prepared
from the nematic liquid crystal materials (1-01) to (1-16) and
partially replaced materials thereof can be used by optionally
mixing them. As a matter of course, such application methods can be
carried out including those which are described in the following
examples.
EXAMPLES
[0251] Examples of the present invention are given below by way of
illustration and not by way of limitation.
[0252] In this connection, measurement of the phase transition
temperature was carried out by jointly using a polarizing
microscope equipped with a temperature controlling stage and a
differential scanning calorimeter (DSC). Also, the structure of
each compound was confirmed by magnetic resonance spectrum
(.sup.1H-NMR, .sup.13C-NMR or .sup.19F-NMR), infrared resonance
spectrum (IR), mass spectrum (MS) and the like means.
[0253] In the following, "%" means "% by weight".
Example 1
Synthesis of 2,6-difluoro-4-(3-butenyl)benzoic acid
[0254] 242
(1-a) Synthesis of 3,5-difluorobenzaldehyde
[0255] A 28 g portion of magnesium turnings was suspended in 60 ml
of tetrahydrofuran (THF) to which was subsequently added dropwise
800 ml of THF solution containing 200 g of
3,5-difluoro-1-bromobenzene at such a rate that the solvent was
gently refluxed. After the dropwise addition, the mixture was
stirred at room temperature for 1 hour and then 91 g of
N,N-dimethylformamide (DMF) was added dropwise thereto. After the
dropwise addition, this was further stirred at room temperature for
1 hour, mixed with 1,000 ml of 10% hydrochloric acid and again
stirred for 1 hour. This was extracted with 1,000 ml of ethyl
acetate, washed twice with saturated brine and then dried with
anhydrous sodium sulfate. By evaporating the solvent, 125 g of
3,5-difluorobenzaldehyde was obtained.
(1-b) Synthesis of 3,5-difluorobenzyl alcohol
[0256] A 20 g portion of sodium borohydride was suspended
(partially dissolved) in 80 ml of ethanol, and 380 ml of ethanol
solution containing 125 g of 3,5-difluorobenzaldehyde to the
suspension which was cooled in an ice bath. After the dropwise
addition, this was stirred for 1 hour, the solvent was evaporated
and the resulting residue was mixed with 400 ml of water. This was
extracted with 700 ml of ethyl acetate, washed with water and
saturated brine in that order and then dried with anhydrous sodium
sulfate. By evaporating the solvent, 120 g of 3,5-difluorobenzyl
alcohol was obtained.
(1-c) Synthesis of 3,5-difluorobenzyl bromide
[0257] A 120 ml portion of 48% hydrobromic acid was added to 120 g
of 3,5-difluorobenzyl alcohol. At room temperature, 120 ml of
sulfuric acid was added dropwise thereto, and the mixture after the
dropwise addition was stirred for 3 hours. The reaction solution
was poured onto crashed ice, extracted with 600 ml of hexane,
washed with water and saturated brine in that order and then dried
with anhydrous sodium sulfate. By evaporating the solvent, 176 g of
3,5-difluorobenzyl bromide was obtained.
(1-d) Synthesis of 3,5-difluoro-1-(3-butenyl)benzene
[0258] A 176 g portion of 3,5-difluorobenzyl bromide was dissolved
in 300 ml of THF to which was subsequently added dropwise 450 ml of
allyl magnesium chloride THF solution (2 mol/l) at room
temperature. This was stirred for 1 hour and then mixed with 300 ml
of water. This was extracted with 800 ml of hexane, washed twice
with saturated brine and then dried with anhydrous sodium sulfate.
After evaporation of the solvent, the resulting residue was
distilled (79-82.degree. C./20 mmHg) to obtain 104 g of
3,5-difluoro-1-(3-butenyl)benzene.
(1-e) Synthesis of 2,6-difluoro-4-(3-butenyl)benzoic acid
[0259] A 50 g portion of 3,5-difluoro-1-(3-butenyl)benzene was
dissolved in 200 ml of THF, and the solution was cooled to
-60.degree. C. A 190 ml portion of n-butyl lithium hexane solution
(1.59 mol/l) was added dropwise thereto at such a rate that the
solution was kept at -40.degree. C. or lower, and the mixture after
the dropwise addition was stirred for 1 hour. Carbon dioxide was
bubbled into the resulting solution at such a rate that the
reaction system was kept at -40.degree. C. or lower. When
exothermic reaction was calmed down, this was stirred for
additional 1 hour and returned to room temperature. This was mixed
with 130 ml of 10% hydrochloric acid, extracted with 400 ml of
ethyl acetate, washed twice with saturated brine and then dried
with anhydrous sodium sulfate. By evaporating the solvent, 62 g of
2,6-difluoro-4-(3-butenyl)benzoic acid was obtained.
Example 2
Synthesis of 2-fluoro-4-(3-pentenyl)benzoic acid
[0260] 243
(2-a) Synthesis of
2-(4-formyl-2-fluoro)phenyl-4,4-dimethyl-1,3-oxazolidin- e
[0261] A Grignard reagent was prepared by allowing
2-(4-bromo-2-fluoro)phe- nyl-4,4-dimethyl-1,3-oxazolidine (this was
synthesized by treating 4-bromo-2-fluorobenzoic acid with thionyl
chloride to convert it into acid chloride which was subsequently
allowed to react with 2-amino-2-methyl-1-propanol and then with
thionyl chloride) to react with magnesium in THF. This was allowed
to react with DMF in the same manner as described in the
aforementioned step (1-a) to obtain
2-(4-formyl-2-fluoro)phenyl-4,4-dimethyl-1,3-oxazolidine in the
form of white crystals.
(2-b) Synthesis of
2-(4-hydroxymethyl-2-fluoro)phenyl-4,4-dimethyl-1,3-oxa-
zolidine
[0262] By reducing
2-(4-formyl-2-fluoro)phenyl-4,4-dimethyl-1,3-oxazolidin- e obtained
in the above step (2-a) with sodium borohydride in the same manner
as described in the aforementioned step (1-b),
2-(4-hydroxymethyl-2-fluoro)phenyl-4,4-dimethyl-1,3-oxazolidine was
obtained in the form of white crystals.
(2-c) Synthesis of
2-(4-bromomethyl-2-fluoro)phenyl-4,4-dimethyl-1,3-oxazo- lidine
[0263]
2-(4-Hydroxymethyl-2-fluoro)phenyl-4,4-dimethyl-1,3-oxazolidine
obtained in the above step (2-b) was dissolved in a mixed solution
of THF and methane tetrabromide, and the solution was mixed with
triphenylphosphine and heated under reflux for 1 hour. After
cooling, this was mixed with hexane and stirred, and the thus
precipitated triphenylphosphine was removed by filtration. After
evaporation of the solvent, the resulting residue was
recrystallized from hexane to obtain
2-(4-bromomethyl-2-fluoro)phenyl-4,4-dimethyl-1,3-oxazolidine in
the form of white crystals.
(2-d) Synthesis of
2-[4-(3-pentyne-1-yl)-2-fluoro]phenyl-4,4-dimethyl-1,3--
oxazolidine
[0264] A Grignard reagent prepared from 1-chloro-2-butyne was added
dropwise to THF solution of
2-(4-bromomethyl-2-fluoro)phenyl-4,4-dimethyl- -1,3-oxazolidine.
Thereafter, in the same manner as described in the aforementioned
step (1-d), 2-[4-(3-pentyne-1-yl)-2-fluoro]phenyl-4,4-dime-
thyl-1,3-oxazolidine was obtained in the form of white
crystals.
(2-e) Synthesis of
2-[4-(trans-3-penten-1-yl)-2-fluoro]phenyl-4,4-dimethyl-
-1,3-oxazolidine
[0265] Lithium was dissolved in liquid ammonia cooled at
-40.degree. C., and to this solution was added dropwise THF
solution of
2-[4-(3-pentyne-1-yl)-2-fluoro]phenyl-4,4-dimethyl-1,3-oxazolidine
obtained in the above step (2-d) and t-butyl alcohol. This was
mixed with ammonium chloride and then ammonia was evaporated. The
resulting residue was dissolved in toluene and washed with water
and then the solvent was evaporated to obtain
2-[trans-4-(3-penten-1-yl)-2-fluoro]phenyl-4,4-dimet-
hyl-1,3-oxazolidine in the form of white crystals.
(2-f) Synthesis of 2-fluoro-4-(trans-3-penten-1-yl)benzoic acid
[0266]
2-[4-(Trans-3-penten-1-yl)-2-fluoro]phenyl-4,4-dimethyl-1,3-oxazoli-
dine obtained in the above step (2-e) was dissolved in ethanol, and
the solution was mixed with 10% hydrochloric acid and stirred at
room temperature for 4 hours. After evaporation of the greater part
of ethanol, the resulting residue was extracted with toluene and
the thus obtained crude product was recrystallized from hexane to
obtain 2-fluoro-4-(trans-3-penten-1-yl)benzoic acid in the form of
white crystals.
Example 3
Synthesis of 3-fluoro-4-cyanophenyl
2,6-difluoro-4-(3-buten-1-yl)benzoate (I)-1
[0267] 244
[0268] A 15 g portion of 2,6-difluoro-4-(3-buten-1-yl)benzoic acid
obtained in Example 1 was dissolved in 45 ml of dichloromethane,
and the solution was mixed with 13 g of thionyl chloride and 0.1 ml
of pyridine and heated under reflux for 6 hours. The acid chloride
obtained by evaporation of the solvent and 10 g of
3-fluoro-4-cyanophenol were dissolved in 60 ml of dichloromethane,
and 9 g of pyridine was added dropwise to the resulting solution at
room temperature. After the dropwise addition, this was stirred for
1 hour and then mixed with 60 ml of 10% hydrochloric acid. The
resulting organic layer was separated, washed with water, saturated
sodium bicarbonate solution, water and saturated brine in that
order and then dried with anhydrous sodium sulfate. After
evaporation of the solvent, the resulting residue was purified by a
silica gel column chromatography (toluene) and then recrystallized
from methanol to obtain 13 g of 3-fluoro-4-cyanophenyl
2,6-difluoro-4-(3-buten-1-yl)benzoate.
[0269] The following compounds are obtained in the same manner.
[0270] 4-Cyanophenyl 2,6-difluoro-4-(3-buten-1-yl)benzoate
[0271] 3,5-Difluoro-4-cyanophenyl
2,6-difluoro-4-(3-buten-1-yl)benzoate
[0272] 4-Cyanophenyl
2,6-difluoro-4-(trans-3-penten-1-yl)benzoate
[0273] 3-Fluoro-4-cyanophenyl
2,6-difluoro-4-(trans-3-penten-1-yl)benzoate
[0274] 3,5-Difluoro-4-cyanophenyl
2,6-difluoro-4-(trans-3-penten-1-yl)benz- oate
[0275] 4-Cyanophenyl
2,6-difluoro-4-(trans-3-hexen-1-yl)benzoate
[0276] 3-Fluoro-4-cyanophenyl
2,6-difluoro-4-(trans-3-hexen-1-yl)benzoate
[0277] 3,5-Difluoro-4-cyanophenyl
2,6-difluoro-4-(trans-3-hexen-1-yl) benzoate
Example 4
Synthesis of 3,5-difluoro-4-cyanophenyl
2-fluoro-4-(trans-3-penten-1-yl)be- nzoate (I)-2
[0278] 3,5-Difluoro-4-cyanophenyl
2-fluoro-4-(trans-3-penten-1-yl)benzoate (I)-2 was obtained from
2-fluoro-4-(trans-3-penten-1-yl)benzoic acid obtained in Example 2
in the same manner as described in Example 3.
[0279] The following compounds are obtained in the same manner.
[0280] 4-Cyanophenyl 2-fluoro-4-(trans-3-penten-1-yl)benzoate
[0281] 3-Fluoro-4-cyanophenyl
2-fluoro-4-(trans-3-penten-1-yl)benzoate
[0282] 4-Cyanophenyl 2-fluoro-4-(3-buten-1-yl)benzoate
[0283] 3-Fluoro-4-cyanophenyl 2-fluoro-4-(3-buten-1-yl)benzoate
[0284] 3,5-Difluoro-4-cyanophenyl
2-fluoro-4-(3-buten-1-yl)benzoate
[0285] 4-Cyanophenyl 2-fluoro-4-(trans-3-hexen-1-yl)benzoate
[0286] 3-Fluoro-4-cyanophenyl
2-fluoro-4-(trans-3-hexen-1-yl)benzoate
[0287] 3,5-Difluoro-4-cyanophenyl
2-fluoro-4-(trans-3-hexen-1-yl)benzoate.
[0288] The following describes compositions of the present
invention in detail. In the compositions of the following examples,
--(CH.sub.2).sub.2-- and --C.sub.2H.sub.4-- or --(CH.sub.2).sub.4--
and --C.sub.4H.sub.8-- are identical with each other.
[0289] In the examples, physical property characteristics of liquid
crystal compositions and display characteristics of liquid crystal
displays constituting TN-LCD are as follows.
[0290] T.sub.N-I: nematic phase-isotropic liquid phase transition
temperature (.degree. C.)
[0291] T.sub..fwdarw.N: solid phase- or smectic phase-nematic phase
transition temperature (.degree. C.)
[0292] .DELTA..epsilon.: dielectric anisotropy at 20.degree. C.
[0293] .DELTA.n: birefringence at 20.degree. C.
[0294] .eta.: viscosity at 20.degree. C. (c.p.)
[0295] Vth: threshold voltage at 20.degree. C. when TN-LCD is
constructed (V)
[0296] .gamma.: ratio of sharpness, saturation voltage (Vsat) to
Vth at 20.degree. C.
[0297] .tau.r=.tau.d: time when both items become equal at
20.degree. C., wherein .tau.r is rise time from 0 V when a
predetermined voltage is applied, and .tau.d is decay time when the
applied voltage is released.
[0298] Chemical stability of compositions was evaluated by putting
2 g of each liquid crystal composition into an ampoule tube,
sealing the tube after vacuum degassing and subsequent nitrogen
replacement and then carrying out 1 hour of heating acceleration
test at 150.degree. C. Each of the liquid crystal compositions was
measured for its specific resistance before the test, specific
resistance after the heating acceleration test, voltage holding
ratio before the test and voltage holding ratio after the heating
acceleration test.
[0299] In this connection, one or a plurality of the compounds
shown in the Examples can be used by replacing them by certain
compounds of the general formulae (I-1) to (III-4) depending on
desired purpose or use, and illustrative compounds in such a case
are represented by the following forms.
[0300] Liquid crystal component A
[0301] A case of general formula (I-10) Compound (2-11): side chain
group (I-ah) basic structure (I-10)
[0302] A case of general formula (I-13) Compound (2-12): side chain
group (I-ah) basic structure (I-13)
[0303] A case of general formula (I-16) Compound (2-13): side chain
group (I-ah) basic structure (I-16)
[0304] Liquid crystal component B
[0305] A case of general formula (II-1) Compound (2-21): side chain
group (II-5a) basic structure (II-1a) polar group (II-6a)
[0306] A case of general formula (II-2) Compound (2-22): side chain
group (II-5a) basic structure (II-2a) polar group (II-6a)
[0307] A case of general formula (II-3) Compound (2-23): side chain
group (II-5a) basic structure (II-3a) polar group (II-6a)
[0308] A case of general formula (II-4) Compound (2-24): side chain
group (II-5a) basic structure (II-1a) polar group (II-6a)
[0309] Liquid crystal component C
[0310] A case of general formula (III-1) Compound (2-31): side
chain group (III-5b) basic structure (III-1a) side chain group
(III-5b)
[0311] A case of general formula (III-2) Compound (2-32): side
chain group (III-5b) basic structure (III-2a) side chain group
(III-5b)
[0312] A case of general formula (III-3) Compound (2-33): side
chain group (III-5b) basic structure (III-3a) side chain group
(III-5b)
[0313] A case of general formula (III-4) Compound (2-34): side
chain group (III-5b) basic structure (III-4a) side chain group
(III-5b)
Definition of Compounds
[0314] Liquid crystal component A 245
[0315] Liquid crystal component B 246
[0316] Liquid crystal component C 247
Example 5 and Comparative Example 1
[0317] A host liquid crystal composition (H) of the following
composition 248
[0318] (mixture of equivalent amounts) comprising compounds of the
present invention represented by the general formula (III-1b) was
prepared. This composition corresponds to the liquid crystal
component C of the present invention. Various characteristics of
this composition were measured. The results are as follows.
[0319] T.sub.N-I: 72.5.degree. C.
[0320] T.sub..fwdarw.N: +17.degree. C.
[0321] .DELTA..epsilon.: -1.3
[0322] .DELTA.n: 0.085
[0323] Vth: -
[0324] A liquid crystal composition (H-A) for comparison use
comprising 90% of the host liquid crystal (H) and 10% of a
conventionally used compound of the following formula (A) 249
[0325] was prepared and its various characteristics were measured.
The results are as follows.
[0326] T.sub.N-I: 65.5.degree. C.
[0327] .DELTA..epsilon.: 3.0
[0328] .DELTA.n: 0.093
[0329] Vth: 2.38 V
[0330] Next, a liquid crystal composition (H-1) was prepared by
adding the same amount (10%) of the compound (I)-1 of the present
invention shown in Table 1 to the host liquid crystal (H), and
various characteristics of the resulting composition were measured.
The results are as follows.
[0331] T.sub.N-I: 62.0.degree. C.
[0332] .DELTA..epsilon.: 2.6
[0333] .DELTA.n: 0.088
[0334] Vth: 1.96 V
[0335] The composition (H-1) of the present invention showed a
T.sub.N-I value of 62.0.degree. C. which was slightly lower than
that of the composition (H-A). Also, it can be seen that its
threshold voltage (Vth) was reduced by a factor of 0.4 V or more
regardless of the 10% or more reduction in its dielectric
anisotropy (.DELTA..epsilon.). On the other hand, the response was
not slowed. Next, the composition (H-1) was allowed to stand at
0.degree. C., but precipitation of crystals and phase separation
were not observed even after one week of standing. In addition,
when it was crystallized by allowing it to stand at -40.degree. C.,
its melting point was measured to be 4.degree. C.
Comparative Example 2
[0336] A liquid crystal composition (H-B) for comparison use was
prepared by adding the same amount (10%) of a conventionally used
compound represented by the following formula (B) 250
[0337] to the host liquid crystal (H) in the same manner as
described in Example 5 and Comparative Example 1, and various
characteristics of the resulting composition were measured. The
results are as follows.
[0338] T.sub.N-I: 64.1.degree. C.
[0339] .DELTA..epsilon.: 3.4
[0340] .DELTA.n: 0.091
[0341] Vth: 2.30 V
[0342] The T.sub.N-I value of (H-B) was 64.1.degree. C. which was
slightly lower than the case of (H-A) but slightly higher than the
case of (H-1). Its threshold voltage was reduced only slightly in
comparison with (H-A) and far beyond the case of (H-1).
Comparative Example 3
[0343] A liquid crystal composition (H-C) for comparison use was
prepared by adding the same amount (10%) of a conventionally used
compound represented by the following formula (C) 251
[0344] to the host liquid crystal (H) in the same manner as
described above, and various characteristics of the resulting
composition were measured. The results are as follows.
[0345] T.sub.N-I: 63.0.degree. C.
[0346] .DELTA..epsilon.: 3.5
[0347] .DELTA.n: 0.089
[0348] Vth: 2.15 V
[0349] The T.sub.N-I value of (H-C) was 63.0.degree. C. which was
almost equivalent to the case of (H-1). Also, dielectric anisotropy
of (H-C) was considerably large and, because of this, its threshold
voltage was markedly improved in comparison with (H-A) and (H-B).
However, regardless of its larger dielectric anisotropy in
comparison with (H-1), its threshold voltage is higher by a factor
of about 0.2 V so that its reducing effect is far beyond the
target. In addition, when the composition (H-C) was allowed to
stand at 0.degree. C., it was crystallized within 3 days, and its
melting point when measured was a high value of 18.degree. C.
[0350] On the basis of the above results, it is evident that the
compound of general formula (I) of the present invention has
excellent threshold voltage reducing effect and also is excellent
in terms of miscibility, in comparison with the conventional high p
type phenyl benzoate derivatives.
Example 6
[0351] Next, a liquid crystal composition (H-2) was prepared by
adding the same amount (10%) of the compound (I)-2 of the present
invention shown in Table 1 to the host liquid crystal (H), and
various characteristics of the resulting composition were measured.
The results are as follows.
[0352] T.sub.N-I: 66.0.degree. C.
[0353] .DELTA..epsilon.: 3.7
[0354] .DELTA.n: 0.091
[0355] Vth: 1.89 V
[0356] The composition (H-2) showed a T.sub.N-I value of
62.5.degree. C. which was slightly higher than that of the
composition (H-1). It can be seen that its dielectric anisotropy
(.DELTA..epsilon.) is larger than that of (H-1) and its threshold
voltage (Vth) was sharply reduced. Also, when the composition (H-2)
was allowed to stand at 0.degree. C., precipitation of crystals and
phase separation were not observed even after one week of
standing.
Example 7 and Comparative Example 4
[0357] Liquid crystal compositions composed of a mixture of the
above-described host liquid crystal H and a compound of formula
(I)-1 or (I)-3 shown below which corresponds to the liquid crystal
component A as the essential component of the present invention
were prepared. Further, liquid crystal compositions composed of a
mixture of the above-described host liquid crystal H and a compound
of a formula (D) or (E) shown below were also prepared for
comparison use. 252
[0358] With regard to the liquid crystal composition which contains
the compound of formula (I)-1, five liquid crystal compositions
were prepared by adjusting the content of the compound of formula
(I)-1 to 10% by weight, 15% by weight, 20% by weight, 25% by weight
or 30% by weight. With regard to the liquid crystal composition
which contains the compound of formula (D), liquid crystal
compositions were prepared in the same manner as the case of the
compound of formula (I)-1. With regard to the liquid crystal
composition which contains the compound of formula (I)-3, three
liquid crystal compositions were prepared by adjusting the content
of the compound of formula (I)-3 to 10% by weight, 15% by weight or
20% by weight. With regard to the liquid crystal composition which
contains the compound of formula (E), liquid crystal compositions
were prepared in the same manner as the case of the compound of
formula (I)-3.
[0359] Using each of the thus prepared liquid crystal compositions,
viscosity at 20.degree. C. and threshold voltage were measured. The
results are shown in FIG. 1.
[0360] As is evident from the results shown in FIG. 1, it was
confirmed that the nematic liquid crystal composition of the
present invention obtained by adding the compound of formula (I)-1
or (I)-3, which corresponds to the liquid crystal component A as
the essential component of the nematic liquid crystal composition
of the present invention, to the host liquid crystal (H) composed
of the liquid crystal component C, has smaller viscosity against
driving voltage when compared with the comparative liquid crystal
composition which contains the compound (D) or (E) and is therefore
different from the composition of the present invention.
[0361] This effect is apt to be achieved when the liquid crystal
component C composed of two or more compounds having a dielectric
anisotropy of from -10 to 2 has smaller viscosity, and it is
desirable that the liquid crystal component C alone has a viscosity
of 25 c.p. or less, preferably 15 c.p. or less, more preferably 10
c.p. or less, most preferably 8 c.p. or less. Particularly, when
compounds of general formulae (I-10) to (I-18) having alkenyl
groups as their side chain groups are used as the liquid crystal
component A, it is desirable for improving viscosity to use as the
liquid crystal component C compounds of general formulae (III-1a)
to (III-1d), (III-2a), (III-2f), (III-3a) and (III-3h), or as
particularly illustrative compounds, compounds of the subgroups
(III-ai) to (III-av), (III-bi) to (III-biii) and (III-ci) to
(III-ciii). By the use of such compounds, viscosity of the nematic
liquid crystal composition containing compounds of groups A4 to A6
is further improved.
Example 8
[0362] A nematic liquid crystal composition (3-01) comprising the
following compounds
9 (% by weight) (3-0101) 253 4 (3-0102) 254 3 (3-0103) 255 5
(3-0104) 256 3 (3-0105) 257 9 (3-0106) 258 9 (3-0107) 259 8
(3-0108) 260 8 (3-0109) 261 5 (3-0110) 262 5 (3-0111) 263 4
(3-0112) 264 10 (3-0113) 265 11 (3-0114) 266 8 (3-0115) 267 9
[0363] was prepared and various characteristics of the composition
were measured. The results are as follows.
[0364] T.sub.N-I: 85.2.degree. C.
[0365] T.sub..fwdarw.N: 30.0.degree. C.
[0366] Vth: 1.61 V
[0367] .DELTA..epsilon.: 7.2
[0368] .DELTA.n: 0.169
[0369] .eta.: 20.0 c.p.
[0370] Specific resistance before the test: 8.4.times.10.sup.12
.OMEGA..multidot.cm
[0371] Specific resistance after heating acceleration test:
4.0.times.10.sup.12 .OMEGA..multidot.cm
[0372] Since this nematic liquid crystal composition has high
specific resistance after the heating acceleration test, it can be
understood that it is stable against heat. Also, when twisted
nematic and super twisted nematic liquid crystal display systems
were prepared using this composition as a constituting material, it
was confirmed that they were excellent display systems which do not
generate flicker.
[0373] In addition, a mixed liquid crystal composition was prepared
by adding a chiral substance "S-811" (manufactured by Merck) to
this nematic liquid crystal composition. On the other hand, a cell
for STN-LCD use having a twist angle of 220 degree was prepared by
effecting formation of the orientation film through the rubbing of
an organic film of "Sun Ever 610" (manufactured by Nissan Chemical
Industries) on the facing transparent flat electrode. The
aforementioned mixed liquid crystal composition was injected into
the thus prepared cell to construct a liquid crystal display
system, and its display characteristics were measured. As the
result, a liquid crystal display system was obtained which showed
STN-LCD display characteristics having particularly excellent
effects in terms of low threshold voltage, high multiplexing
properties, improved flicker and crosstalk phenomena on the display
screen, quick response and viewing angle characteristics having
small parallax.
[0374] In this connection, the chiral substance was added in such
an amount that natural helical pitch P of the mixed liquid crystal
composition and cell thickness d of the display cell became
.DELTA.n.multidot.d=0.85 and d/P=0.53 by the addition of the chiral
substance.
[0375] In addition, when a TN-LCD having a cell thickness d of 3.0
.mu.m was constructed and its display characteristics were
measured, its threshold voltage was 1.39 V and response time was
1.2 msec. A liquid crystal display system showing TN-LCD display
characteristics was obtained.
[0376] A nematic liquid crystal composition (3-01-01) is prepared
by changing the compound (3-0103) of the nematic liquid crystal
composition shown in this example to a compound: side chain group
(I-al) basic structure (I-16). Nematic liquid crystal compositions
prepared in this manner are shown in the following as "Composition
(3-01-01)=compound (3-0103).fwdarw.compound: side chain group
(I-al) basic structure (I-16)".
[0377] Composition (3-01-02)=compound (3-0103).fwdarw.compound:
side chain group (I-al) basic structure (I-16) polar group
[0378] Composition (3-01-03)=compound (3-0103).fwdarw.compound:
side chain group (I-am) basic structure (I-16) polar group
[0379] Composition (3-01-04)=compound (3-0103).fwdarw.compound:
side chain group (I-an) basic structure (I-16) polar group
[0380] Composition (3-01-05)=compound (3-0103).fwdarw.compound:
side chain group (I-al) basic structure (I-17) polar group
[0381] Composition (3-01-06)=compound (3-0103).fwdarw.compound:
side chain group (I-am) basic structure (I-18) polar group
[0382] Composition (3-01-07)=compound (3-0103).fwdarw.compound:
side chain group (I-an) basic structure (I-19) polar group
[0383] Similar to this example, these nematic liquid crystal
compositions (3-01-01) to (3-01-07) showed excellent display
characteristics.
Example 9
[0384] A nematic liquid crystal composition (3-01) comprising the
following compounds
10 (% by weight) (3-0201) 268 3 (3-0202) 269 5 (3-0203) 270 8
(3-0204) 271 7 (3-0205) 272 5 (3-0206) 273 10 (3-0207) 274 6
(3-0208) 275 6 (3-0209) 276 5 (3-0210) 277 10 (3-0211) 278 15
(3-0212) 279 15 (3-0213) 280 5
[0385] was prepared and various characteristics of the composition
were measured. The results are as follows.
[0386] T.sub.N-I: 100.0.degree. C.
[0387] T.sub..fwdarw.N: 40.0.degree. C.
[0388] Vth: 1.80 V
[0389] .DELTA..epsilon.: 6.9
[0390] .DELTA.n: 0.114
[0391] .eta.: 12.3 c.p.
[0392] Specific resistance before the test: 4.1.times.10.sup.13
.OMEGA..multidot.cm
[0393] Specific resistance after heating acceleration test:
1.0.times.10.sup.13 .OMEGA..multidot.cm
[0394] Since this nematic liquid crystal composition has high
specific resistance after the heating acceleration test, it can be
understood that it is stable against heat. Also, when twisted
nematic and super twisted nematic liquid crystal display systems
were prepared using this composition as a constituting material, it
was confirmed that they were excellent display systems which do not
generate flicker.
[0395] In addition, when temperature-dependency of threshold
voltage at from -10.degree. C. to 60.degree. C. was measured as an
electro-optical characteristic using the thus obtained TN-LCD, it
was 1.7 mV/.degree. C. showing that a liquid crystal display system
having excellent display characteristics was obtained.
Example 10
[0396] A nematic liquid crystal composition (3-03) comprising the
following compounds
11 (% by weight) (3-0301) 281 5 (3-0302) 282 5 (3-0303) 283 8
(3-0304) 284 2 (3-0305) 285 5 (3-0306) 286 5 (3-0307) 287 5
(3-0308) 288 5 (3-0309) 289 15 (3-0310) 290 15 (3-0311) 291 5
(3-0312) 292 5 (3-0313) 293 10 (3-0314) 294 10
[0397] was prepared and various characteristics of the composition
were measured. The results are as follows.
[0398] T.sub.N-I: 74.0.degree. C.
[0399] T.sub..fwdarw.N: 20.0.degree. C.
[0400] Vth: 1.32 V
[0401] .DELTA..epsilon.: 10.8
[0402] .DELTA.n: 0.130
[0403] .eta.: 13.9 c.p.
[0404] In addition, a mixed liquid crystal composition was prepared
by adding a chiral substance "S-811" (manufactured by Merck) to
this nematic liquid crystal composition. On the other hand, a cell
for STN-LCD use having a twist angle of 220 degree was prepared by
effecting formation of the orientation film through the rubbing of
an organic film of "Sun Ever 610" (manufactured by Nissan Chemical
Industries) on the facing transparent flat electrode. The
aforementioned mixed liquid crystal composition was injected into
the thus prepared cell to construct a liquid crystal display
system, and its display characteristics were measured. As the
result, a liquid crystal display system was obtained which showed
STN-LCD display characteristics having particularly excellent
effects in terms of low threshold voltage, high multiplexing
properties, improved flicker and crosstalk phenomena on the display
screen, quick response and viewing angle characteristics having
small parallax.
[0405] In this connection, the chiral substance was added in such
an amount that natural helical pitch P of the mixed liquid crystal
composition and cell thickness d of the display cell became
.DELTA.n.multidot.d=0.85 and d/P=0.53 by the addition of the chiral
substance.
Example 11
[0406]
12 (% by weight) (3-0401) 295 5 (3-0402) 296 5 (3-0403) 297 5
(3-0404) 298 5 (3-0405) 299 5 (3-0406) 300 5 (3-0407) 301 5
(3-0408) 302 5 (3-0409) 303 5 (3-0410) 304 5 (3-0411) 305 15
(3-0412) 306 15 (3-0413) 307 10 (3-0414) 308 10
[0407] was prepared and various characteristics of the composition
were measured. The results are as follows.
[0408] T.sub.N-I: 82.1.degree. C.
[0409] T.sub..fwdarw.N: 30.0.degree. C.
[0410] Vth: 0.81 V
[0411] .DELTA..epsilon.: 21.2
[0412] .DELTA.n: 0.107
[0413] .eta.: 36.5 c.p.
[0414] Specific resistance before the test: 8.0.times.10.sup.11
.OMEGA..multidot.cm
[0415] Specific resistance after heating acceleration test:
3.2.times.10.sup.11 .OMEGA..multidot.cm
[0416] Since this nematic liquid crystal composition has high
specific resistance after the heating acceleration test, it can be
understood that it is stable against heat. Also, when a twisted
nematic liquid crystal display systems was prepared using this
composition as a constituting material, it was confirmed that it
was excellent display system which does not generate flicker.
[0417] In addition, when temperature-dependency of threshold
voltage at from -10.degree. C. to 40.degree. C. was measured as an
electro-optical characteristic using the thus obtained TN-LCD, it
was 1.0 mV/.degree. C. showing that a liquid crystal display system
having excellent display characteristics was obtained. Its response
at a low temperature was also excellent.
Example 12
[0418] A nematic liquid crystal composition (3-05) comprising the
following compounds
13 (% by weight) (3-0501) 309 5 (3-0502) 310 10 (3-0503) 311 10
(3-0504) 312 10 (3-0505) 313 10 (3-0506) 314 10 (3-0507) 315 10
(3-0508) 316 5 (3-0509) 317 5 (3-0510) 318 5 (3-0511) 319 5
(3-0512) 320 10 (3-0513) 321 5
[0419] was prepared and various characteristics of the composition
were measured. The results are as follows.
[0420] T.sub.N-I: 83.0.degree. C.
[0421] T.sub..fwdarw.N: -70.0.degree. C.
[0422] Vth: 1.32 V
[0423] .DELTA..epsilon.: 10.0
[0424] .DELTA.n: 0.094
[0425] .eta.: 19.1 c.p.
[0426] Specific resistance before the test: 4.1.times.10.sup.12
.OMEGA..multidot.cm
[0427] Specific resistance after heating acceleration test:
1.0.times.10.sup.12 .OMEGA..multidot.cm
[0428] Since this nematic liquid crystal composition has high
specific resistance after the heating acceleration test, it can be
understood that it is stable against heat. Also, when a liquid
crystal display cell having an orientation film of "Sun Ever 610"
was prepared using this composition as a constituting material, it
showed a high tilt angle.
Example 13
[0429]
14 (% by weight) (3-0801) 322 8 (3-0802) 323 5 (3-0803) 324 8
(3-0804) 325 4 (3-0805) 326 4 (3-0806) 327 7 (3-0807) 328 5
(3-0808) 329 5 (3-0809) 330 10 (3-0810) 331 17 (3-0811) 332 7
(3-0812) 333 6 (3-0813) 334 7 (3-0814) 335 7
[0430] was prepared and various characteristics of the composition
were measured. The results are as follows.
[0431] T.sub.N-I: 91.7.degree. C.
[0432] T.sub..fwdarw.N: -50.0.degree. C.
[0433] Vth: 1.32 V
[0434] .DELTA..epsilon.: 18.9
[0435] .DELTA.n: 0.145
[0436] .eta.: 44.8 c.p.
[0437] In addition, a mixed liquid crystal composition was prepared
by adding a chiral substance "S-811" (manufactured by Merck) to
this nematic liquid crystal composition. On the other hand, a cell
for STN-LCD use having a twist angle of 240 degree was prepared by
effecting formation of the orientation film through the rubbing of
an organic film of "Sun Ever 610" (manufactured by Nissan Chemical
Industries) on the facing transparent flat electrode. The
aforementioned mixed liquid crystal composition was injected into
the thus prepared cell to construct a liquid crystal display
system, and its display characteristics were measured. As the
result, a liquid crystal display system was obtained which showed
STN-LCD display characteristics having particularly excellent
effects in terms of low threshold voltage, high multiplexing
properties, improved flicker and crosstalk phenomena on the display
screen and viewing angle characteristics having small parallax.
[0438] In this connection, the chiral substance was added in such
an amount that natural helical pitch P of the mixed liquid crystal
composition and cell thickness d of the display cell became
.DELTA.n.multidot.d=0.85 and d/P=0.53 by the addition of the chiral
substance.
[0439] STN-LCD display characteristics at a twist angle of 240
degree
15 Vth 0.98 V .gamma. 1.027 .DELTA.(Vth)/.DELTA.(T) 1.3 mV/.degree.
C.
[0440] The following nematic liquid crystal compositions are
prepared in the same manner as described in Example 8.
[0441] Composition (3-08-01)=compound (3-0808).fwdarw.compound:
side chain group (I-al) basic structure (I-16) polar group
[0442] Composition (3-08-02)=compound (3-0808).fwdarw.compound:
side chain group (I-am) basic structure (I-16) polar group
[0443] Composition (3-08-03)=compound (3-0808).fwdarw.compound:
side chain group (I-an) basic structure (I-16) polar group
[0444] Composition (3-08-04)=compound (3-0808).fwdarw.compound:
side chain group (I-al) basic structure (I-17) polar group
[0445] Composition (3-08-05)=compound (3-0808).fwdarw.compound:
side chain group (I-am) basic structure (I-17) polar group
[0446] Composition (3-08-06)=compound (3-0808).fwdarw.compound:
side chain group (I-an) basic structure (I-17) polar group
[0447] Composition (3-08-07)=compound (3-0808).fwdarw.compound:
side chain group (I-d) basic structure (I-7) polar group
[0448] Composition (3-08-08)=compound (3-0808).fwdarw.compound:
side chain group (I-al) basic structure (I-15) polar group
[0449] Composition (3-08-09)=compound (3-0808).fwdarw.compound:
side chain group (I-am) basic structure (I-15) polar group
[0450] Composition (3-08-10)=compound (3-0808).fwdarw.compound:
side chain group (I-an) basic structure (I-15) polar group
[0451] Similar to this example, these nematic liquid crystal
compositions (3-08-01) to (3-08-10) showed excellent display
characteristics. Among them, composition (3-08-02), composition
(3-08-05) and composition (3-08-09) showed more excellent
characteristics.
Example 14
[0452]
16 (% by weight) (3-0901) 336 9 (3-0902) 337 5 (3-0903) 338 10
(3-0904) 339 8 (3-0905) 340 8 (3-0906) 341 10 (3-0907) 342 8
(3-0908) 343 7 (3-0909) 344 5 (3-0910) 345 10 (3-0911) 346 10
(3-0912) 347 3 (3-0913) 348 7
[0453] was prepared and various characteristics of the composition
were measured. The results are as follows.
[0454] T.sub.N-I: 89.1.degree. C.
[0455] T.sub..fwdarw.N: -50.0.degree. C.
[0456] Vth: 1.12 V
[0457] .DELTA..epsilon.: 16.7
[0458] .DELTA.n: 0.144
[0459] .eta.: 32.1 c.p.
[0460] In addition, a mixed liquid crystal composition was prepared
by adding a chiral substance "S-811" (manufactured by Merck) to
this nematic liquid crystal composition. On the other hand, a cell
for STN-LCD use having a twist angle of 240 degree was prepared by
effecting formation of the orientation film through the rubbing of
an organic film of "Sun Ever 610" (manufactured by Nissan Chemical
Industries) on the facing transparent flat electrode. The
aforementioned mixed liquid crystal composition was injected into
the thus prepared cell to construct a liquid crystal display
system, and its display characteristics were measured. As the
result, a liquid crystal display system was obtained which showed
STN-LCD display characteristics having particularly excellent
effects in terms of low threshold voltage, high multiplexing
properties, improved flicker and crosstalk phenomena on the display
screen and viewing angle characteristics having small parallax.
[0461] In this connection, the chiral substance was added in such
an amount that natural helical pitch P of the mixed liquid crystal
composition and cell thickness d of the display cell became
.DELTA.n.multidot.d=0.85 and d/P=0.53 by the addition of the chiral
substance.
[0462] STN-LCD display characteristics at a twist angle of 240
degree
17 Vth 0.99 V .gamma. 1.029 .DELTA.(Vth)/.DELTA.(T) 1.2 mV/.degree.
C.
[0463] The following nematic liquid crystal compositions are
prepared in the same manner as described in Example 8.
[0464] Composition (3-09-01)=compound (3-0904).fwdarw.compound:
side chain group (I-al) basic structure (I-16) polar group
[0465] Composition (3-09-02)=compound (3-0904).fwdarw.compound:
side chain group (I-am) basic structure (I-16) polar group
[0466] Composition (3-09-03)=compound (3-0904).fwdarw.compound:
side chain group (I-an) basic structure (I-16) polar group
[0467] Composition (3-09-04)=compound (3-0901).fwdarw.compound:
side chain group (I-al) basic structure (I-10) polar group
[0468] Composition (3-09-05)=compound (3-0901).fwdarw.compound:
side chain group (I-am) basic structure (I-10) polar group
[0469] Composition (3-09-06)=compound (3-0901).fwdarw.compound:
side chain group (I-an) basic structure (I-10) polar group
[0470] Composition (3-09-07)=compound (3-0905).fwdarw.compound:
side chain group (I-al) basic structure (I-17) polar group
[0471] Composition (3-09-08)=compound (3-0905).fwdarw.compound:
side chain group (I-am) basic structure (I-17) polar group
[0472] Composition (3-09-09)=compound (3-0905).fwdarw.compound:
side chain group (I-an) basic structure (I-17) polar group
[0473] Composition (3-09-10)=compound (3-0905).fwdarw.compound:
side chain group (I-am) basic structure (I-14) polar group
[0474] Similar to this example, these nematic liquid crystal
compositions (3-09-01) to (3-09-10) showed excellent display
characteristics. Among them, composition (3-09-01), composition
(3-09-02) and composition (3-09-08) showed further improved
threshold voltage and temperature-dependency and
frequency-dependency thereof.
Example 15
[0475]
18 (% by weight) (3-1001) 349 9 (3-1002) 350 5 (3-1003) 351 10
(3-1004) 352 8 (3-1005) 353 8 (3-1006) 354 10 (3-1007) 355 8
(3-1008) 356 7 (3-1009) 357 5 (3-1010) 358 10 (3-1011) 359 10
(3-1012) 360 3 (3-1013) 361 7
[0476] was prepared and various characteristics of the composition
were measured. The results are as follows.
[0477] T.sub.N-I: 89.0.degree. C.
[0478] T.sub..fwdarw.N: 50.0.degree. C.
[0479] Vth: 1.13 V
[0480] .DELTA..epsilon.: 16.9
[0481] .DELTA.n: 0.144
[0482] .eta.: 33.6 c.p.
[0483] In addition, a mixed liquid crystal composition was prepared
by adding a chiral substance "S-811" (manufactured by Merck) to
this nematic liquid crystal composition. On the other hand, a cell
for STN-LCD use having a twist angle of 240 degree was prepared by
effecting formation of the orientation film through the rubbing of
an organic film of "Sun Ever 610" (manufactured by Nissan Chemical
Industries) on the facing transparent flat electrode. The
aforementioned mixed liquid crystal composition was injected into
the thus prepared cell to construct a liquid crystal display
system, and its display characteristics were measured. As the
result, a liquid crystal display system was obtained which showed
STN-LCD display characteristics having particularly excellent
effects in terms of low threshold voltage, high multiplexing
properties, improved flicker and crosstalk phenomena on the display
screen and viewing angle characteristics having small parallax.
[0484] In this connection, the chiral substance was added in such
an amount that natural helical pitch P of the mixed liquid crystal
composition and cell thickness d of the display cell became
.DELTA.n.multidot.d=0.85 and d/P=0.53 by the addition of the chiral
substance.
[0485] STN-LCD display characteristics at a twist angle of 240
degree
19 Vth 1.13 V .gamma. 1.031 .DELTA.(Vth)/.DELTA.(T) 1.3 mV/.degree.
C.
Example 16
[0486] The nematic liquid crystal composition (1-16) of the present
invention showed the following additional characteristics. When
wavelength dispersion of the birefringence of the nematic liquid
crystal composition was measured, the light wavelength ratio of 400
nm to 650 nm was 1.15 or more. Since this liquid crystal material
shows more larger retardation based on the difference in the light
wavelength, it is useful in a novel reflection type liquid crystal
color display system in which color display is carried out making
use of birefringence of liquid crystal and retardation film without
using color filter layers.
Example 17
[0487] The nematic liquid crystal compositions of the present
invention, particularly (1-10), (1-11), (1-13), (1-14), (3-02),
(3-03), (3-05), (3-09) and (3-10), showed the following additional
characteristics. When a formula
(.omega.d=2.times.10.sup.12.times.S.sup.-1.4031 was defined as the
relaxation frequency which is defined using a liquid crystal
constituting factor of these liquid crystal compositions,
S=(.eta..times.<a>.sup.3).sup.-1 {wherein .eta. represents
viscosity of a liquid crystal composition (unit, c.p.) and
<a> represents average molecular length of the liquid crystal
composition (unit, .ANG.)}, and F was defined as the execution
frequency practically applied to the liquid crystal layer, which is
defined by the frame frequency and/or duty numbers related to the
driving of the liquid crystal composition as a display, a function
of 1.0.times.10.sup.2.gtoreq-
..omega.d/F.gtoreq.5.0.times.10.sup.-1 was found within the driving
temperature range. Because of this, a problem of not changing
driving voltage within the frequency range corresponding to various
cases of the multiplexing properties or of sudden increase in the
driving voltage at a low temperature due to increase in the
multiplexing properties (duty numbers) can be made better. Such a
characteristic feature seems to be originated from the construction
of the liquid crystal component A. As a consequence, liquid crystal
display systems having improved display characteristics can be
obtained by the use of the liquid crystal composition of the
present invention. Particularly, excellent driving characteristics
and display characteristics were obtained in the TN-LCD and STN-LCD
liquid crystal display systems which require large quantity of
information.
[0488] The nematic liquid crystal composition of the present
invention can provide liquid crystal materials in response to
desired purposes even by its addition in a small amount without
spoiling other characteristics. More particularly, it provides a
nematic liquid crystal composition which has such a temperature
range that low temperature driving can be effected, shows more
quicker response against driving voltage and can effect the driving
at lower voltage. In consequence, liquid crystal display systems in
which flicker and crosstalk phenomena on the display screen are
improved can be obtained by the use of the liquid crystal
composition of the present invention. In addition, thickness d of
the liquid crystal layer can be reduced when the birefringence is
increased and the response characteristics can therefore be
improved, so that excellent driving characteristics and display
characteristics can be obtained particularly in the TN-LCD and
STN-LCD liquid crystal display systems which require large quantity
of information.
[0489] While the invention has been described in detail and with
reference to specific examples thereof, it will be apparent to one
skilled in the art that various changes and modifications can be
made therein without departing from the spirit and scope
thereof.
* * * * *