Nematic liquid crystal composition

Abstract

A liquid crystal composition exhibits a positive dielectric anisotropy and sufficiently low viscosity without decreasing or increasing refractive index anisotropy or nematic phase-isotropic liquid phase transition temperature, and does not cause display failures. The liquid crystal composition contains one or more compounds selected from compounds represented by general formula (LC0) and one or more compounds selected from a group of compounds represented by general formula (LC1) to general formula (LC5), in which the liquid crystal composition contains one or more compounds in which at least one of A.sup.01, A.sup.02, and A.sup.11 to A.sup.42 in general formulae (LC0) to (LC4) represents a tetrahydropyran-2,5-diyl group.

Claims

1. A liquid crystal composition having a positive dielectric anisotropy and containing one or more compounds selected from compounds represented by general formula (LC0) and one or more compounds selected from a group of compounds represented by general formula (LC1) to general formula (LC5), wherein the liquid crystal composition contains one or more compounds in which at least one of A.sup.01 and A.sup.02 in general formula (LC0) represents a tetrahydropyran-2,5-diyl group: ##STR00045## wherein in the formulae, R.sup.01 to R.sup.41 each independently represent an alkyl group having 1 to 15 carbon atoms where one or more CH.sub.2 in the alkyl group may each be substituted with O, CHCH, CO, OCO, COO, CC, CF.sub.2O, or OCF.sub.2 so long as oxygen atoms are not directly adjacent to each other and one or more hydrogen atoms in the alkyl group may each be substituted with a halogen; R.sup.51 and R.sup.52 each independently represent an alkyl group having 1 to 15 carbon atoms where one or more CH.sub.2 in the alkyl group may each be substituted with O, CHCH, CO, OCO, COO, or CC so long as oxygen atoms are not directly adjacent to each other, and may each represent OCF.sub.3 or CF.sub.3 when A.sup.51 or A.sup.53 described below represents a cyclohexane ring; A.sup.01 to A.sup.42 each independently represent any one of structures below: ##STR00046## wherein in the structures, one or more CH.sub.2 in the cyclohexane ring may each be substituted with O so long as oxygen atoms are not directly adjacent to each other; in the structures, one or more CH in the benzene ring may each be substituted with N so long as nitrogen atoms are not directly adjacent to each other; and X.sup.61 and X.sup.62 each independently represent H, Cl, F, CF.sub.3, or OCF.sub.3; A.sup.51 to A.sup.53 each independently represent any one of structures below: ##STR00047## wherein in the formulae, one or more CH.sub.2CH.sub.2 in the cyclohexane ring may each be substituted with CHCH, CF.sub.2O, or OCF.sub.2 and one or more CH in the benzene ring may each be substituted with N so long as nitrogen atoms are not directly adjacent to each other; X.sup.01 represents a hydrogen atom or a fluorine atom; X.sup.11 to X.sup.43 each independently represent H, Cl, F, CF.sub.3, or OCF.sub.3; Y.sup.01 to Y.sup.41 each represent Cl, F, OCHF.sub.2, CF.sub.3, or OCF.sub.3; Z.sup.01 and Z.sup.02 each independently represent a single bond, CHCH, CC, CH.sub.2CH.sub.2, (CH.sub.2).sub.4, OCF.sub.2, or CF.sub.2O; Z.sup.31 to Z.sup.42 each independently represent a single bond, CHCH, CC, CH.sub.2CH.sub.2, (CH.sub.2).sub.4, OCF.sub.2, or CF.sub.2O where at least one of Z.sup.31 and Z.sup.32 that are present represents a group other than a single bond; Z.sup.51 and Z.sup.52 each independently represent a single bond, CHCH, C, CH.sub.2CH.sub.2, (CH.sub.2).sub.4, OCH.sub.2, CH.sub.2O, OCF.sub.2 or CF.sub.2O; m.sup.01 to m.sup.51 each independently represent an integer of 0 to 3; m.sup.01+m.sup.02, m.sup.31+m.sup.32, and m.sup.41+m.sup.42 are each independently 1, 2, 3, or 4; and when a plurality of A.sup.01, A.sup.03, A.sup.23, A.sup.31, A.sup.32, A.sup.41, A.sup.42, A.sup.52, Z.sup.01, Z.sup.02, Z.sup.31, Z.sup.32, Z.sup.41, Z.sup.42, and/or Z.sup.52 are present, they may be the same or different.

2. The liquid crystal composition according to claim 1, wherein X.sup.01 in general formula (LC0) represents F.

3. The liquid crystal composition according to claim 1, wherein the liquid crystal composition contains one or more compounds selected from the group consisting of compounds represented by general formula (LC2-1) to general formula (LC2-14) as the compound represented by general formula (LC2): ##STR00048## ##STR00049## wherein in the formulae, X.sup.23, X.sup.24, X.sup.25, and X.sup.26 each independently represent a hydrogen atom Cl, F, CF.sub.3, or OCF.sub.3, and X.sup.22, R.sup.21, and Y.sup.21 are the same as those in claim 1.

4. The liquid crystal composition according to claim 1, wherein the liquid crystal composition contains one or more compounds selected from the group consisting of compounds represented by general formula (LC3-1) to general formula (LC3-32) as the compound represented by general formula (LC3): ##STR00050## ##STR00051## ##STR00052## ##STR00053## ##STR00054## wherein in the formulae, X.sup.33, X.sup.34, X.sup.35, X.sup.36, X.sup.37, and X.sup.38 each independently represent H, Cl, F, CF.sub.3, or OCF.sub.3, and X.sup.32, R.sup.31, A.sup.31, Y.sup.31, and Z.sup.31 are the same as those in claim 1.

5. The liquid crystal composition according to claim 1, wherein the liquid crystal composition contains one or more compounds selected from the group consisting of compounds represented by general formula (LC4-1) to general formula (LC4-23) as the compound represented by general formula (LC4): ##STR00055## ##STR00056## ##STR00057## ##STR00058## wherein in the formulae, X.sup.44, X.sup.45, X.sup.46, and X.sup.47 each independently represent H, Cl, F, CF.sub.3, or OCF.sub.3, and X.sup.42, X.sup.43, R.sup.41, and Y.sup.41 are the same as those in claim 1.

6. The liquid crystal composition according to claim 1, wherein the liquid crystal composition contains one or more compounds selected from the group consisting of compounds represented by general formula (LC5-1) to general formula (LC5-26) as the compound represented by general formula (LC5): ##STR00059## ##STR00060## ##STR00061## the formulae, R.sup.51 and R.sup.52 are the same as those in claim 1.

7. The liquid crystal composition according to claim 1, wherein the liquid crystal composition contains 5 to 50% by mass of one or more compounds in which at least one of A.sup.01 and A.sup.02 in general formula (LC0) represents a tetrahydropyran-2,5-diyl group.

8. The liquid crystal composition according to claim 1, wherein the liquid crystal composition contains one or more optically active compounds.

9. The liquid crystal composition according to claim 1, wherein the liquid crystal composition contains one or more compounds in which at least one of Z.sup.01, Z.sup.02, Z.sup.31 to Z.sup.42, Z.sup.51, and Z.sup.52 in general formula (LC0) and general formula (LC3) to general formula (LC5) represents CF.sub.2O or OCF.sub.2.

10. The liquid crystal composition according to claim 1, wherein the liquid crystal composition contains 30 to 70% by mass of the compound represented by general formula (LC5) and has a viscosity of 20 mPa.Math.s or less at 20 C.

11. The liquid crystal composition according to claim 1, wherein the liquid crystal composition contains one or more polymerizable compounds.

12. The liquid crystal composition according to claim 1, wherein the liquid crystal composition contains one or more antioxidants.

13. The liquid crystal composition according to claim 1, wherein the liquid crystal composition contains one or more UV absorbers.

14. A liquid crystal display device using the liquid crystal composition according to claim 1.

15. An active matrix driving liquid crystal display device using the liquid crystal composition according to claim 1.

16. A TN-mode, OCB-mode, ECB-mode, IPS-mode, or VA-IPS-mode liquid crystal display device using the liquid crystal composition according to claim 1.

17. A polymer-stabilized TN-mode, OCB-mode, ECB-mode, IPS-mode, or VA-IPS-mode liquid crystal display device that uses the liquid crystal composition according to claim 11 and is produced by polymerizing the polymerizable compounds in the liquid crystal composition in the absence or presence of applied voltage.

18. The liquid crystal display device according to claim 14, wherein an alignment layer that has a surface that comes into contact with liquid crystal molecules and causes the liquid crystal molecules to align horizontally, tilt, or align vertically includes an alignment film containing at least one compound selected from polyimide (PI), polyamide, chalcone, cinnamate, and cinnamoyl.

19. The liquid crystal display device according to claim 18, wherein the alignment layer according to claim 18 further includes a polymerizable liquid crystal compound or a polymerizable non-liquid crystal compound.

20. The liquid crystal display device according to claim 18, wherein an alignment film prepared by an optical alignment technology is formed as the alignment layer at the surface that comes into contact with the liquid crystal composition.

Description

DESCRIPTION OF EMBODIMENTS

(1) A liquid crystal composition according to the invention of the present application contains one or more compounds selected from compounds represented by general formula (LC0) above and one or more compounds selected from a compound group consisting of compounds represented by general formulae (LC1) to (LC5). Since a liquid crystal composition containing compounds represented by general formula (LC0) and compounds represented by general formulae (LC1) to (LC5) exhibits a stable liquid crystal phase even at low temperature, the liquid crystal composition can be regarded as a practical liquid crystal composition.

(2) In general formulae (LC0) to (LC5), R.sup.01 to R.sup.52 preferably each independently represent an alkyl group having 1 to 8 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, or an alkoxy group having 1 to 8 carbon atoms and are preferably linear. When R.sup.01 to R.sup.52 are to represent alkenyl groups, selection is preferably made from groups represented by formulae (R1) to (R5):

(3) ##STR00005##
(In each formula, the black dot represents a bonding point to a ring.)

(4) In the case where A.sup.01, A.sup.01, A.sup.21, A.sup.31, A.sup.41, A.sup.51, and A.sup.53 each represent a trans-1,4-cyclohexylene group, groups represented by formulae (R1), (R2), and (R4) are more preferable. It is yet more preferable to contain one or more compounds represented by general formula (LC5) in which at least one selected from R.sup.51 and R.sup.53 represents an alkenyl group represented by a formula selected from formulae (R1) to (R5). A.sup.01 to A.sup.42 preferably each independently represent a trans-1,4-cyclohexylene group, a 1,4-phenylene group, a 3-fluoro-1,4-phenylene group, a 3,5-difluoro-1,4-phenylene group, or a tetrahydropyran-2,5-diyl group. In the case where some of A.sup.01 to A.sup.42 are to represent a tetrahydropyran-2,5-diyl group, A.sup.01, A.sup.11, A.sup.21, A.sup.31, and A.sup.41 preferably represent this group. Examples of preferable compounds containing a tetrahydropyran-2,5-diyl group include compounds represented by general formula (LC0-7) to general formula (LC0-9), general formula (LC0-23), general formula (LC0-24), general formula (LC0-26), general formula (LC0-27), general formula (LC0-20), general formula (LC0-40), general formula (LC0-51) to general formula (LC0-53), general formula (LC0-110), general formula (LC0-111), general formula (LC2-9) to general formula (LC2-14), general formula (LC3-23) to general formula (LC3-32), general formula (LC4-12) to general formula (LC4-14), general formula (LC4-16), general formula (LC4-19), and general formula (LC4-22). In such a case, at least one compound selected from this compound group is more preferably contained in order to achieve the object of the present invention.

(5) A.sup.51 to A.sup.53 preferably each independently represent a trans-1,4-cyclohexylene group, a 1,4-phenylene group, a 3-fluoro-1,4-phenylene group, or a 2-fluoro-1,4-phenylene group.

(6) Z.sup.01 and Z.sup.02 preferably each independently represent a single bond, CHCH, CC, CH.sub.2CH.sub.2, OCF.sub.2, or CF.sub.2O. In the case where one of Z.sup.01 and Z.sup.02 that are present represents CHCH, CC, CH.sub.2CH.sub.2, (CH.sub.2).sub.4, OCF.sub.2, or CF.sub.2O, the other preferably represents a single bond. Z.sup.01 and Z.sup.02 preferably both represent a single bond.

(7) Z.sup.31 to Z.sup.42 preferably each independently represent a single bond, CHCH, CC, CH.sub.2CH.sub.2, OCH.sub.2, CH.sub.2O, OCF.sub.2, or CF.sub.2O. In the case where one of Z.sup.31 to Z.sup.42 that are present represents CHCH, CC, CH.sub.2CH.sub.2, (CH.sub.2).sub.4, OCF.sub.2, or CF.sub.2O, the others preferably each represent a single bond.

(8) Z.sup.51 and Z.sup.52 preferably each independently represent a single bond, CHCH, CC, CH.sub.2CH.sub.2, OCF.sub.2, or CF.sub.2O. In the case where one of Z.sup.51 and Z.sup.52 that are present represents CHCH, CC, CH.sub.2CH.sub.2, (CH.sub.2).sub.4, OCH.sub.2, CH.sub.2O, OCF.sub.2, or CF.sub.2O, the other preferably represents a single bond. More preferably, Z.sup.51 and Z.sup.52 both represent a single bond.

(9) X.sup.01 in general formula (LC0) is preferably F since a significantly low viscosity () is achieved relative to a high dielectric anisotropy () or the same level of dielectric anisotropy (). X.sup.11 to X.sup.43 preferably each independently represent H or F, and X.sup.11, X.sup.21, X.sup.31, and X.sup.41 preferably each represent F.

(10) Y.sup.01 to Y.sup.41 particularly preferably each independently represent F, CF.sub.3, or OCF.sub.3. While m.sup.01 to m.sup.51 may each independently represent an integer of 0 to 23, m.sup.01+m.sup.02 is particularly preferably 1 or 2, m.sup.21 is particularly preferably 0, m.sup.31+m.sup.32 is particularly preferably 1, 2, or 3, and m.sup.41+m.sup.42 is particularly preferably 1 or 2.

(11) The liquid crystal compound represented by general formula (LC0) is preferably a compound represented by any one of general formula (LC0-a) to (LC0-h) (in the formulae, R.sup.01, A.sup.01, A.sup.02, A.sup.03, Z.sup.01, Z.sup.02, X.sup.01, and Y.sup.01 are the same as those in general formula (LC0) and when two or more A.sup.01 and A.sup.03, and/or Z.sup.01 and Z.sup.02 are present, they may be the same or different).

(12) ##STR00006##

(13) More preferable are the compounds represented by general formula (LC0-1) to general formula (LC0-111) below:

(14) ##STR00007## ##STR00008## ##STR00009## ##STR00010## ##STR00011## ##STR00012## ##STR00013## ##STR00014## ##STR00015## ##STR00016## ##STR00017## ##STR00018## ##STR00019##
(In the formulae, R is the same as R.sup.01 in general formula (LC0), F, CF.sub.3, OCF.sub.3 denotes that Y.sup.01 each independently represent one of F, CF.sub.3, and OCF.sub.3, and (F) denotes H or F serving as a substituent.) Compounds represented by general formula (LC0-1) to general formula (LC0-19) are particularly preferable since they have high dielectric anisotropy (), notably low viscosity (), and good compatibility. Compounds represented by general formulae (LC0-20) to general formula (LC0-111) are particularly preferable since they have high dielectric anisotropy (), relatively low viscosity (11), and a high nematic phase-isotropic liquid phase transition temperature (T.sub.ni).

(15) The compounds represented by general formula (LC2) are more preferably compounds represented by general formula (LC2-1) to general formula (LC2-14) below:

(16) ##STR00020## ##STR00021##
(In the formulae, X.sup.23, X.sup.24, X.sup.25, and X.sup.26 each independently represent a hydrogen atom, Cl, F, CF.sub.3, or OCF.sub.3, and X.sup.22, R.sup.21, and Y.sup.21 are the same as those in general formula (LC2)). The group of compounds represented by general formula (LC2-1) to general formula (LC2-4) and general formula (LC2-9) to general formula (LC2-11) is more preferable.

(17) The compounds represented by general formula (LC3) are more preferably compounds represented by general formula (LC3-1) to general formula (LC3-32) below:

(18) ##STR00022## ##STR00023## ##STR00024## ##STR00025## ##STR00026##
(In the formulae, X.sup.33, X.sup.34, X.sup.35, X.sup.36, X.sup.37, and X.sup.38 each independently represent H, Cl, F, CF.sub.3, or OCF.sub.3, and X.sup.32, R.sup.31, A.sup.31, Y.sup.31, and Z.sup.31 are the same as those in general formula (LC3).) Among these, the group of the compounds represented by general formula (LC3-5), general formula (LC3-15), and general formula (LC3-20) to general formula (LC3-32) is more preferably used in combination with the essential component of the present invention represented by general formula (LC0). More preferably, a compound selected from the group of compounds represented by general formula (LC3-20) and general formula (LC3-21) with X.sup.33 and X.sup.34 each representing F and/or the group of tetrahydropyran-ring-containing compounds represented by general formula (LC3-25), general formula (LC3-26), and general formula (LC3-30) to general formula (LC3-32) are preferably used in combination with the essential component of the present invention represented by general formula (LC0).

(19) The compounds represented by general formula (LC4) are more preferably compounds represented by general formula (LC4-1) to general formula (LC4-23) below:

(20) ##STR00027## ##STR00028## ##STR00029## ##STR00030##
(In the formulae, X.sup.44, X.sup.45, X.sup.46, and X.sup.47 each independently represent H, Cl, F, CF.sub.3, or OCF.sub.3, and X.sup.42, X.sup.43, R.sup.41, and Y.sup.41 are the same as those in general formula (LC4).) Among these, the group of compounds represented by general formula (LC4-1) to general formula (LC4-3), general formula (LC4-6), general formula (LC4-9), general formula (LC4-10), and general formula (LC4-12) to general formula (LC4-17) are more preferably used in combination with the essential component of the present invention represented by general formula (LC0). Furthermore, among these, a compound selected from the group of compounds represented by general formula (LC4-9) to general formula (LC4-11) and general formula (LC4-15) to general formula (LC4-17) with X.sup.44 and/or X.sup.45 representing F is more preferably used in combination with the essential component of the present invention represented by general formula (LC0).

(21) The compounds represented by general formula (LC5) are more preferably compounds represented by general formula (LC5-1) to general formula (LC5-26) below:

(22) ##STR00031## ##STR00032## ##STR00033##
(In the formulae, R.sup.51 and R.sup.52 are the same as those in general formula (LC5).) Among these, the group of compounds represented by general formula (LC5-1) to general formula (LC5-8), general formula (LC5-14), general formula (LC5-16), and general formula (LC5-18) to general formula (LC5-26) is particularly preferably used in combination with the essential component of the present invention represented by general formula (LC0). At least one of R.sup.51 and R.sup.52 in general formula (LC5-1) and general formula (LC5-4) preferably represents an alkenyl group and more preferably an alkenyl group selected from those represented by formulae (R1) to (R5) below.

(23) ##STR00034##

(24) One or more compounds represented by general formula (LC5) are preferably contained. The content thereof is preferably 20 to 70% by mass and more preferably 30 to 70% by mass.

(25) The liquid crystal composition of the present invention contains a compound represented by general formula (LC0) and a compound selected from the group of compounds represented by general formula (LC1) to general formula (LC5). Of these compounds, at least one compound is a compound having a tetrahydropyran-2,5-diyl group and the content thereof is preferably in the range of 5 to 50% by mass and more preferably in the range of 10 to 40% by mass. The compound having a tetrahydropyran-2,5-diyl group which is an essential component of the liquid crystal composition of the present invention is preferably a compound represented by general formula (LC0), at least one of A.sup.01 and A.sup.02 in general formula (LC0) preferably represents a tetrahydropyran-2,5-diyl group, and the content thereof is preferably 5 to 50% by mass.

(26) The liquid crystal composition of the present invention preferably has a viscosity of 20 mPa.Math.s or less at 20 C.

(27) The liquid crystal composition of the present invention may contain one or more optically active compounds. The optically active compounds may be any capable of twisting and aligning liquid crystal molecules. Since twisting normally changes depending on temperature, plural optically active compounds may be used to obtain a desired temperature dependence. In order not to adversely affect the nematic liquid crystal phase temperature range, viscosity, and the like, it is preferable to select and use optically active compounds that have a powerful twisting effect. Examples of such optically active compounds to be contained include liquid crystals such as cholesteric nonanoate and compounds represented by general formula (Ch-1) to general formula (Ch-6) below:

(28) ##STR00035##
(In the formulae, R.sub.c1, R.sub.c2, and R* each independently represent an alkyl group having 1 to 15 carbon atoms where one or more CH.sub.2 in the alkyl group may each be substituted with O, CHCH, CO, OCO, COO, CC, CF.sub.2O, or OCF.sub.2 so long as oxygen atoms are not directly adjacent to each other and one or more hydrogen atoms in the alkyl group may each be substituted with a halogen; R* includes at least one optically active branched chain group or halogen substituent; Z.sub.c1 and Z.sub.c2 each independently represent a single bond, CHCH, CC, CH.sub.2CH.sub.2, (CH.sub.2).sub.4, COO, OCO, OCH.sub.2, CH.sub.2O, OCF.sub.2, or CF.sub.2O; D.sub.1 and D.sub.2 each represent a cyclohexane ring or a benzene ring where one or more CH.sub.2 in the cyclohexane ring may each be substituted with O so long as oxygen atoms are not directly adjacent to each other, one or more CH.sub.2CH.sub.2 in the ring may each be substituted with CHCH, CF.sub.2O, or OCF.sub.2, one or more CH in the benzene ring may each be substituted with N so long as nitrogen atoms are not directly adjacent to each other, and one or more hydrogen atoms in the ring may each be substituted with F, Cl, or CH.sub.3; t.sub.1 and t.sub.2 each represent 0, 1, 2, or 3; and MG*, Q.sub.c1, and Q.sub.c2 each represent the structure below:

(29) ##STR00036##
(In the formula, D.sub.3 and D.sub.4 each represent a cyclohexane ring or a benzene ring, one or more CH.sub.2 in the cyclohexane ring may each be substituted with O so long as oxygen atoms are not directly adjacent to each other, one or more CH.sub.2CH.sub.2 in the ring may each be substituted with CHCH, CF.sub.2O, or OCF.sub.2, one or more CH in the benzene ring may each be substituted with N so long as nitrogen atoms are not directly adjacent to each other, and one or more hydrogen atoms in the ring may each be substituted with F, Cl, or CH.sub.3.)

(30) The liquid crystal composition of the present invention may contain one or more polymerizable compounds. The polymerizable compounds are preferably discotic liquid crystal compounds which have a benzene derivative, a triphenylene derivative, a truxene derivative, a phthalocyanine derivative, or a cyclohexane derivative as a core at the molecular center and linear alkyl groups, linear alkoxy groups, or substituted benzoyloxy groups as side chains radially substituting the core.

(31) To be specific, the polymerizable compounds are preferably compounds represented by general formula (PC):

(32) ##STR00037##
(In the formula, P.sub.1 represents a polymerizable functional group, Sp.sub.1 represents a spacer group having 0 to 20 carbon atoms, Q.sub.p1 represents a single bond, O, NH, NHCOO, OCONH, CHCH, CO, COO, OCO, OCOO, OOCO, CHCH, CHCHCOO, OCOCHCH, or CC, p.sub.1 and p.sub.2 each independently represent 1, 2, or 3, MG.sub.p represents a mesogenic group or a mesogenic supporting group, and R.sub.p1 represents a halogen atom, a cyano group, or an alkyl group having 1 to 25 carbon atoms where one or more CH.sub.2 group in the alkyl group may each be substituted with O, S, NH, N(CH.sub.3), CO, COO, OCO, OCOO, SCO, COS, or CC so long as oxygen atoms are not directly adjacent to each other, or R.sub.p1 may represent P.sub.2-Sp.sub.2-Q.sub.p2- where P.sub.2, Sp.sub.2, and Q.sub.p2 are respectively the same as P.sub.1, Sp.sub.1, and Q.sub.p1.)

(33) More preferably, the polymerizable compounds are those represented by general formula (PC) with MG.sub.p representing the following structure:

(34) ##STR00038##
(In the formula, C.sub.01 to C.sub.03 each independently represent a 1,4-phenylene group, a 1,4-cyclohexylene group, a 1,4-cyclohexenyl group, a tetrahydropyran-2,5-diyl group, a 1,3-dioxane-2,5-diyl group, a tetrahydrothiopyran-2,5-diyl group, a 1,4-bicyclo(2,2,2)octylene group, a decahydronaphthalene-2,6-diyl group, a pyridine-2,5-diyl group, a pyrimidine-2,5-diyl group, a pyradine-2,5-diyl group, a 1,2,3,4-tetrahydronaphthalene-2,6-diyl group, a 2,6-naphthylene group, a phenanthrene-2,7-diyl group, a 9,10-dihydrophenanthrene-2,7-diyl group, a 1,2,3,4,4a,9,10a-octahydrophenanthrene-2,7-diyl group, or a fluorene-2,7-diyl group; the 1,4-phenylene group, the 1,2,3,4-tetrahydronaphthalene-2,6-diyl group, the 2,6-naphthylene group, the phenanthrene-2,7-diyl group, the 9,10-dihydrophenanthrene-2,7-diyl group, the 1,2,3,4,4a,9,10a-octahydrophenanthrene-2,7-diyl group, and the fluorene-2,7-diyl group may each have, as a substituent, one or more selected from F, Cl, CF.sub.3, OCF.sub.3, a cyano group, an alkyl group having 1 to 8 carbon atoms, an alkoxy group, an alkanoyl group, an alkanoyloxy group, an alkenyl group having 2 to 8 carbon atoms, an alkenyloxy group, an alkenoyl group, and an alkenoyloxy group; Z.sub.p1 and Z.sub.p2 each independently represent COO, OCO, CH.sub.2CH.sub.2, OCH.sub.2, CH.sub.2O, CHCH, CC, CHCHCOO, OCOCHCH, CH.sub.2CH.sub.2COO, CH.sub.2CH.sub.2OCO, COOCH.sub.2CH.sub.2, OCOCH.sub.2CH.sub.2, CONH, NHCO, or a single bond; and p.sub.3 represents 0, 1, or 2.)

(35) In the case where Sp.sub.1 and Sp.sub.2 each independently represent an alkylene group, the alkylene group may be substituted with one or more halogen atoms or CN and one or more CH.sub.2 groups present in this group may each be substituted with O, S, NH, N(CH.sub.2), CO, COO, OCO, OCOO, SCO, COS, or CC so long as oxygen atoms are not directly adjacent to each other. P.sub.1 and P.sub.2 preferably each independently represent a group selected from those represented by general formulae below:

(36) ##STR00039##
(In the formulae, R.sub.p2 to R.sub.p6 each independently represent a hydrogen atom, a halogen atom, or an alkyl group having 1 to 5 carbon atoms.)

(37) To be more specific, the polymerizable compounds represented by general formula (PC) are preferably compounds represented by general formula (PC0-1) to general formula (PC0-6) below:
[Chem. 23]
(P.sub.1-Sp.sub.1-Q.sub.p1.sub.p.sub.1MG.sub.pQ.sub.p2-Sp.sub.2-P.sub.2).sub.p.sub.4(PC0-1)
(P.sub.1-Q.sub.p1.sub.p.sub.1MG.sub.pQ.sub.p2-P.sub.2).sub.p.sub.4(PC0-2)
P.sub.1-Sp.sub.1-Q.sub.p1-MG.sub.p-Q.sub.p2-Sp.sub.2-P.sub.2(PC0-3)
P.sub.1-Q.sub.p1-MG.sub.p-Q.sub.p2-P.sub.2(PC0-4)
P.sub.1-Sp.sub.1-Q.sub.p1-MG.sub.p-R.sub.p1(PC0-5)
P.sub.1-Q.sub.p1-MG.sub.p-R.sub.p1(PC0-6)
(In the formulae, p.sub.4 each independently represent 1, 2, or 3.) The polymerizable compounds represented by general formula (PC0) are more preferably compounds represented by more specific formulae, namely, general formula (PC1-1) to general formula (PC1-9) below:

(38) ##STR00040##
(In the formulae, p.sub.5 represents 0, 1, 2, 3, or 4.)

(39) More preferable are polymerizable compounds represented by general formula (PC) to general formula (PC1-9) with Sp.sub.1, Sp.sub.2, Q.sub.p1, and Q.sub.p2 all representing single bonds, polymerizable compounds with P.sub.1 and P.sub.2 representing a group represented by formula (PC0-a), an acrylate, and/or a methacrylate, polymerizable compounds represented by general formula (PC0-1) and general formula (PC0-2) with p.sub.1 and p.sub.4 satisfying p.sub.1+p.sub.4=1 to 6, and polymerizable compounds represented by general formula (PC1-1) and general formula (PC1-9) with R.sub.p1 representing F, CF.sub.3, OCF.sub.3, CH.sub.3, or OCH.sub.3, where the number of substituents R.sub.p1 is 1, 2, 3, or 4.

(40) Also preferable is a discotic liquid crystal compound represented by general formula (PC) with MG.sub.p representing a group represented by general formula (PC1)-9.

(41) ##STR00041##
(In the formulae, R.sub.7 each independently represent P.sub.1-Sp.sub.1-Q.sub.p1 or a substituent represented by general formula (PC1-e), R.sub.81 and R.sub.82 each independently represent a hydrogen atom, a halogen atom, or a methyl group, R.sub.83 represents an alkoxy group having 1 to 20 carbon atoms, and at least one of hydrogen atoms in the alkoxy group is substituted with a substituent represented by any one of general formulae (PC0-a) to (PC0-d) above.) The amount of the polymerizable compounds used is preferably 0.05 to 2.0% by mass.

(42) The liquid crystal composition of the present invention containing a polymerizable compound is used to manufacture a liquid crystal composition through polymerizing the polymerizable compound. During this process, the amount of the unpolymerized components is preferably decreased to a desired level or less. A liquid crystal composition of the present invention suited for this use preferably contains a compound having a biphenyl group or a terphenyl group as a partial structure in general formula (LC0). More specifically, it is preferable to use 0.1 to 40% by mass of at least one selected from the group of compounds represented by general formula (LC0-4) to general formula (LC0-6), general formula (LC0-10) to general formula (LC0-16), and general formula (LC0-27) to general formula (LC0-107). The compound is preferably used in combination with a polymerizable compound selected from those represented by general formula (PL1-1) to general formula (PL1-3), general formula (PC1-8), and general formula (PC1-9).

(43) The liquid crystal composition may further contain one or more antioxidants and one or more UV absorbers. The antioxidant is preferably selected from those represented by general formula (E-1) and/or general formula (E-2) below:

(44) ##STR00042##
(In the formulae, R.sub.e1 represents an alkyl group having 1 to 15 carbon atoms, one or more CH.sub.2 in the alkyl group may each be substituted with O, CHCH, CO, OCO, COO, CC, CF.sub.2O, or OCF.sub.2 so long as oxygen atoms are not directly adjacent to each other, and one or more hydrogen atoms in the alkyl group may each be substituted with a halogen;
Z.sub.e1 and Z.sub.e2 each independently represent a single bond, CHCH, CC, CH.sub.2CH.sub.2, (CH.sub.2).sub.4, COO, OCO, OCH.sub.2, CH.sub.2O, OCF.sub.2, or CF.sub.2O; and
E.sub.1 represents a cyclohexane ring or a benzene ring, one or more CH.sub.2 in the cyclohexane ring may each be substituted with O so long as oxygen atoms are not directly adjacent to each other, one or more CH.sub.2CH.sub.2 in the ring may each be substituted with CHCH, CF.sub.2O, or OCF.sub.2, one or more CH in the benzene ring may each be substituted with N so long as nitrogen atoms are not directly adjacent to each other, one or more hydrogen atoms in the ring may each be substituted with F, Cl, or CH.sub.3, and q.sub.1 represents 0, 1, 2, or 3.)

(45) The liquid crystal composition according to the present invention can be used in liquid crystal display devices, in particular, active matrix driving liquid crystal display devices of, for example, TN mode, OCB mode, ECB mode, IPS (including FFS electrodes) mode, or VA-IPS mode (including FFS electrodes). Here, the VA-IPS mode refers to a driving mode in which a liquid crystal material having a positive dielectric anisotropy (>0) is vertically aligned with respect to the substrate surface in the absence of applied voltage and liquid crystal molecules are driven by using pixel electrodes and a common electrode arranged on the same substrate surface. Since liquid crystal molecules align in a direction of the curved electric field generated by the pixel electrodes and the common electrode, it is easy to divide pixels into sub-areas to form a multi-domain structure and enhance response. Such a system is referred to as EOC, VA-IPS, etc., according to Non-Patent Literatures Proc. 13th IDW, 97 (1997), Proc. 13th IDW, 175 (1997), SID Sym. Digest, 319 (1998), SID Sym. Digest, 838 (1998), SID Sym. Digest, 1085 (1998), SID Sym. Digest, 334 (2000), and Eurodisplay Proc., 142 (2009). In the present invention, the name VA-IPS is used.

(46) In general, the threshold voltage (Vc) of the Freedericksz transition for TN and ECB mode is determined by the following expression:

(47) $\begin{array}{cc}\mathrm{Vc}=\frac{d_{\mathrm{cell}}}{d_{\mathrm{cell}}+.Math.r_1.Math.}\sqrt{\frac{K11}{\mathrm{.Math.}}}& \left[\mathrm{Math}.1\right]\end{array}$

(48) Vc for STN mode is determined by the following expression:

(49) $\begin{array}{cc}\mathrm{Vc}=\frac{d_{\mathrm{gap}}}{d_{\mathrm{cell}}+.Math.r_2.Math.}\sqrt{\frac{K22}{\mathrm{.Math.}}}& \left[\mathrm{Math}.2\right]\end{array}$

(50) Vc for VA mode is determined by the following expression:

(51) $\begin{array}{cc}\mathrm{Vc}=\frac{d_{\mathrm{cell}}}{d_{\mathrm{cell}}-.Math.r_3.Math.}\sqrt{\frac{K33}{.Math.\mathrm{.Math.}.Math.}}& \left[\mathrm{Math}.3\right]\end{array}$
(In the expressions, Vc denotes the Freedericksz transition (V), denotes the circular constant, d.sub.cell denotes the gap (m) between a first substrate and a second substrate, d.sub.gap denotes the gap (m) between the pixel electrodes and the common electrode, d.sub.ITO denotes the width (m) of the pixel electrodes and/or the common electrode, <r1>, <r2>, and <r3> denote the extrapolation length (m), K11 denotes the splay elastic constant (N), K22 denotes the twist elastic constant (N), K33 denotes the bend elastic constant (N), and denotes the dielectric anisotropy.)

(52) It has been found that the following mathematical expression 4 is applicable to the present invention etc., for VA-IPS mode:

(53) $\begin{array}{cc}\mathrm{Vc}\frac{d_{\mathrm{gap}}-.Math.r^{}.Math.}{d_{\mathrm{ITO}}+.Math.r.Math.}\frac{d_{\mathrm{cell}}}{d_{\mathrm{cell}}-.Math.r_3.Math.}\sqrt{\frac{K33}{.Math.\mathrm{.Math.}.Math.}}& \left[\mathrm{Math}.4\right]\end{array}$
(In the expression, Vc denotes the Freedericksz transition (V), n denotes the circular constant, d.sub.cell denotes the gap (m) between a first substrate and a second substrate, d.sub.gap denotes the gap (m) between the pixel electrodes and the common electrode, d.sub.ITO denotes the width (m) of the pixel electrodes and/or the common electrode, <r>, <r>, and <r3> denote the extrapolation length (m), K33 denotes the bend elastic constant (N), and denotes the dielectric anisotropy.) Mathematical expression 4 shows that the cell structure may be designed to decrease d.sub.gap as much as possible and increase d.sub.ITO as much as possible to achieve low drive voltage and that a liquid crystal composition having with a large absolute value and a low K33 may be selected as the liquid crystal composition to achieve low drive voltage.

(54) The liquid crystal composition of the present invention can be adjusted to exhibit desirable , K11, K33, etc.

(55) The product (n.Math.d) of the refractive index anisotropy (n) of the liquid crystal composition and the gap (d) between the first substrate and the second substrate of a display device is strongly related to viewing angle characteristics and response speed. Accordingly, the gap (d) tends to be as small as 3 to 4 m. The product (n.Math.d) is particularly preferably 0.31 to 0.33 for the TN, ECB, and IPS (liquid crystal aligns substantially horizontal to the substrate surface in the absence of applied voltage) modes. For the VA-IPS mode, the product is preferably 0.20 to 0.59 and more preferably 0.30 to 0.40 if the alignment is vertical with respect to the two substrates. Since the suitable value of the product (n.Math.d) differs depending on the mode of the display device, a liquid crystal composition capable of exhibiting a refractive index anisotropy (n) in various different ranges, such as 0.070 to 0.110, 0.100 to 0.140, or 0.130 to 0.180 is required. In order to obtain a small or relatively small refractive index anisotropy (n) from the liquid crystal composition of the present invention, it is preferable to use 0.1 to 80% by mass of one or more compounds selected from the group consisting of compounds represented by general formula (LC0-1) to general formula (LC0-3), general formula (LC0-7) to general formula (LC0-9), and general formula (LC0-20) to general formula (LC0-30). In order to obtain a large or relatively large refractive index anisotropy (n), it is preferable to use 0.1 to 60% by mass of one or more compounds selected from the group consisting of compounds represented by general formula (LC0-4) to general formula (LC0-6), general formula (LC0-10) to general formula (LC0-16), and general formula (LC0-27) to general formula (LC0-107). For the TN and ECB modes that require the liquid crystal to align substantially horizontal to the substrate surface in the absence of applied voltage, the tilt angle is preferably 0.5 to 7. For the VA-IP mode that requires the liquid crystal to align substantially perpendicular to the substrate surface in the absence of applied voltage, the tilt angle is preferably 85 to 90. In order to have the liquid crystal composition aligned in such a manner, alignment films composed of polyimide (PI), polyamide, chalcone, cinnamate, cinnamoyl, or the like may be provided. The alignment films are preferably formed by using an optical alignment technology. A liquid crystal composition of the present invention containing a compound represented by general formula (LC0) having a partial structure in which X.sup.01 represents F can be easily aligned along the easy axis of the alignment films and the desired tilt angle can be easily formed.

(56) A liquid crystal composition of the present invention containing a compound represented by general formula (PC) as the polymerizable compound can be used to form a polymer-stabilized TN-mode, OCB-mode, ECB-mode, IPS-mode, or VA-IPS mode liquid crystal display device prepared by polymerizing the polymerizable compounds in the liquid crystal composition in the presence or absence of applied voltage.

EXAMPLES

(57) The present invention will now be described in further detail by using Examples which do not limit the scope of the present invention. Note that the % for compositions of Examples and Comparative Examples below means % by mass.

(58) The physical properties of the liquid crystal composition are presented as follows:

(59) T.sub.N-I: nematic phase-isotropic liquid phase transition temperature ( C.)

(60) T-n: lower limit temperature ( C.) of nematic phase

(61) : dielectric constant in a direction perpendicular to the molecular long axis at 25 C.

(62) : dielectric anisotropy at 25 C.

(63) no: refractive index for ordinary rays at 25 C.

(64) n: refractive index anisotropy at 25 C.

(65) Vth: voltage (V) applied to a 6 m-thick cell at which the transmittance changes by 10% when square waves are applied at a frequency of 1 KHz at 25 C.

(66) Viscosity: bulk viscosity (mPa.Math.s) at 20 C.

(67) .sub.1: rotational viscosity (mPa.Math.s)

(68) Compounds are abbreviated as follows:

(69) TABLE-US-00001 TABLE 1 n (numeral) at terminus C.sub.nH.sub.2n+1 -2- CH.sub.2CH.sub.2 -1O- CH.sub.2O -O1- OCH.sub.2 V CO VO COO CFFO CF.sub.2O F F Cl Cl CN CN OCFFF OCF.sub.3 CFFF 0 OCFF OCHF.sub.2 On OC.sub.nH.sub.2n+1 -T- CC ndm- C.sub.nH.sub.2n+1HCCH(CH.sub.2).sub.m1 -ndm (CH.sub.2).sub.n1HCCHC.sub.mH.sub.2m+1 ndmO C.sub.nH.sub.2n+1HCCH(CH.sub.2).sub.m1O Ondm O(CH.sub.2).sub.n1HCCHC.sub.mH.sub.2m+1

(70) ##STR00043##

Example 1

(71) A liquid crystal composition prepared and physical properties thereof are shown below:

(72) TABLE-US-00002 TABLE 2 1d1-Cy-Cy-3 15.0% od1-Cy-Cy-1d1 15.0 2-Cy-Cy-Ph-1 5.0 3-Cy-Cy-Ph-1 7.0 1-PhPh1Ph-3d0 8.0 3-Cy-Cy-Ph3OCFFF 10.0 3-Cy-Cy-CFFOPh3F 5.0 3-Cy-Ph1Ph3CFFOPh3F 10.0 3-PrPh3O1PhOCFFF 15.0 3-PrPh3O1Ph3F 10.0 Tni 72.2 T-n 33.0 Vth 1.42 1 67.0 3.57 8.37 no 1.486 n 0.094 Viscosity 13.1

Comparative Example 1

(73) A liquid crystal composition prepared and physical properties thereof are shown below:

(74) TABLE-US-00003 TABLE 3 1d1-Cy-Cy-3 15.0% od1-Cy-Cy-1d1 15.0 2-Cy-Cy-Ph-1 5.0 3-Cy-Cy-Ph-1 7.0 1-PhPh1Ph-3d0 8.0 3-Cy-Cy-Ph3OCFFF 10.0 3-Cy-Cy-CFFOPh3F 5.0 3-Cy-Ph1Ph3CFFOPh3F 10.0 3-PrPh3-1OPhOCFFF 15.0 3-PrPhO1Ph3F 10.0 Tni 67.0 T-n 33.0 Vth 1.50 1 94.0 3.55 7.87 no 1.485 n 0.093 Viscosity 20.5

(75) This liquid crystal composition does not contain a compound represented by general formula (LC0) having a -Ph3-OCH.sub.2 partial structure disclosed in this application. Although Example 1 has a larger dielectric anisotropy () and a high nematic phase-isotropic liquid phase transition temperature (T.sub.ni), Example 1 has viscosity substantially lower than that of Comparative Example 1, and small .sub.1. This shows that the combination of the present invention has outstanding benefits.

Example 2

(76) A liquid crystal composition prepared and physical properties thereof are shown below:

(77) TABLE-US-00004 TABLE 4 1d1-Cy-Cy-3 10.0% od1-Cy-Cy-1d1 10.0 3-Cy-Cy-2 5.0 3-PrPh3O1PhOCFFF 5.0 3-PrPh3O1Ph3F 5.0 3-PrPh1Ph3O1Ph3F 10.0 3-Pr-Cy-Ph3O1PhOCFFF 5.0 3-Cy-PrPh3O1Ph3F 5.0 3-Cy-Cy-Ph3O1Ph3F 5.0 3-Cy-PhPh3O1Ph3F 5.0 3-PhPh1Ph3O1Ph3F 10.0 3-PhPh1Np3F 5.0 Tni 79.2 T-n 36.0 Vth 1.38 1 76.0 3.86 9.87 no 1.485 n 0.090 Viscosity 14.1

Example 3

(78) A liquid crystal composition prepared and physical properties thereof are shown below:

(79) TABLE-US-00005 TABLE 5 0d1-Cy-Cy-3 10.0% 1d1-Cy-Cy-2 10.0 1d1-Cy-Cy-3 15.0 2-Cy-Cy-Ph-1 2.0 3-Cy-Cy-Ph-1 3.0 3-Pr-Cy-Ph3O1PhOCFFF 5.0 3-Cy-PrPh3O1Ph3F 5.0 3-Cy-Ph3O1PhOCFFF 10.0 3-PhPh3O1PhOCFFF 10.0 3-Cy-Cy-Ph3O1Ph3F 10.0 3-Cy-PhPh3O1Ph3F 10.0 3-PhPh1Ph3O1Ph3F 10.0 Tni 84.6 T-n 31.0 Vth 1.43 1 72.0 3.71 8.41 no 1.488 n 0.095 Viscosity 12.8

Example 4

(80) A liquid crystal composition prepared and physical properties thereof are shown below:

(81) TABLE-US-00006 TABLE 6 1d1-Cy-Cy-2 10.0% 1d1-Cy-Cy-3 15.0 od1-Cy-Cy-1d1 15.0 3-Cy-Cy-2 2.0 2-Cy-Cy-Ph-1 3.0 3-Cy-Cy-Ph-1 5.0 1-PhPh1Ph-3d0 5.0 3-Cy-PhPh3OCFFF 5.0 3-PrPh3O1PhOCFFF 5.0 3-PrPh1Ph3O1Ph3F 10.0 3-Cy-Ph3O1PhOCFFF 10.0 3-PhPh3O1PhOCFFF 5.0 3-Cy-Cy-Ph3O1Ph3F 10.0 Tni 76.0 T-n 39.0 Vth 1.69 1 60.0 3.39 6.40 no 1.486 n 0.090 Viscosity 10.7

Example 5

(82) A liquid crystal composition prepared and physical properties thereof are shown below:

(83) TABLE-US-00007 TABLE 7 Compound Example 5 0d1-Cy-Cy-3 10.0% 1d1-Cy-Cy-2 15.0 1d1-Cy-Cy-3 15.0 od1-Cy-Cy-1d1 5.0 3-Cy-Cy-Ph3OCFFF 5.0 3-Cy-PhPh3OCFFF 5.0 3-Cy-Cy-CFFOPh3F 5.0 3-Cy-Ph1Ph3CFFOPh3F 5.0 3-PrPh1Ph3O1Ph3F 5.0 3-Pr-Cy-Ph3O1PhOCFFF 5.0 3-Cy-PrPh3O1Ph3F 5.0 3-Cy-Ph3O1PhOCFFF 5.0 3-PhPh3O1PhOCFFF 5.0 3-Cy-Cy-Ph3O1Ph3F 5.0 3-Cy-PhPh3O1Ph3F 5.0 Tni 78.9 T-n 36.0 Vth 1.44 1 74.0 3.56 8.22 no 1.484 n 0.081 Viscosity 13.1

Example 6

(84) A liquid crystal composition prepared and physical properties thereof are shown below:

(85) TABLE-US-00008 TABLE 8 0d1-Cy-Cy-3 10.0% 1d1-Cy-Cy-2 10.0 1d1-Cy-Cy-3 10.0 od1-Cy-Cy-1d1 10.0 3-Cy-Cy-Ph-1 7.0 1-PhPh1Ph-3d0 8.0 3-PrPh1Ph3O1Ph3F 10.0 3-Pr-Cy-Ph3O1PhOCFFF 10.0 3-PhPh3O1PhOCFFF 10.0 3-Cy-PhPh3O1Ph3F 5.0 3-PhPh1Ph3O1Ph3F 10.0 Tni 91.8 T-n 36.0 Vth 1.53 1 79.0 3.54 7.52 no 1.490 n 0.110 Viscosity 14.3

Example 7

(86) A vertical alignment film was formed on a first substrate that had a pair of comb-shaped transparent electrodes. Another vertical alignment film was formed on a second substrate that had no electrode structure. The first substrate and the second substrate were formed into an IPS empty cell having a gap spacing of 4.0 m. The liquid crystal composition of Example 1 was poured into the empty cell to prepare a liquid crystal display device.

(87) To 99% of the liquid crystal composition of Example 1, 1% of a polymerizable compound represented by formula (PC-1)-3-1 was added and homogeneously dissolved:

(88) ##STR00044##
As a result, a polymerizable liquid crystal composition CLC-A was obtained. The physical properties of CLC-A were substantially the same as physical properties of the liquid crystal composition of Example 1.
CLC-A was held in the IPS empty cell described above. The liquid crystal cell was then irradiated with ultraviolet light using a high-pressure mercury lamp through a filter that cuts off ultraviolet rays of 300 nm or less while applying 1.8 V square waves at a frequency of 1 KHz. The irradiation was conducted for 600 seconds while adjusting the irradiation intensity at the cell surface to be 20 mW/cm.sup.2. As a result, a vertical-alignment liquid crystal display device in which a polymerizable compound in the polymerizable liquid crystal composition was polymerized was obtained. This display device had significantly high response speed compared to the liquid crystal display device formed by using only the liquid crystal composition of Example 1.