Nematic liquid crystal composition and liquid crystal display device

Abstract

There is provided a liquid crystal composition having a sufficiently low viscosity (), a sufficiently low rotational viscosity (1), a high elastic constant (K.sub.33), and negative with a high absolute value without decreasing the refractive index anisotropy (n) and the nematic phase-isotropic liquid phase transition temperature (T.sub.ni); and a liquid crystal display device with a VA mode or the like that uses the liquid crystal composition and has high display quality and high response speed. The liquid crystal display device that uses the liquid crystal composition of the present invention has a distinguished feature of high-speed response and is particularly useful as an active matrix driving liquid crystal display device. The liquid crystal display device is applicable to a VA mode, PSVA mode, PSA mode, IPS mode, or ECB mode liquid crystal display device.

Claims

1. A liquid crystal composition comprising: a first component comprising one or more fluorobenzene derivatives having a 1-propenyl group represented by general formula (I-1), and one or more fluorobenzene derivatives having a 1-propenyl group represented by general formula (I-2); and one or more liquid crystal compounds having negative with an absolute value of 3 or more as a second component, ##STR00019## in the general formula (I-2), R.sup.11 represents an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, or an alkenyloxy group having 2 to 5 carbon atoms; Z.sup.11 and Z.sup.12 each represent CH.sub.2O,or a single bond; Ring A and Ring B each represent a trans-1,4-cyclohexylene group, a 1,4-phenylene group, or a 1,4-cyclohexenylene group; and m and n each independently represent 0 or 1, ##STR00020## in the general formula (I-2). R.sup.11 represents an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, or an alkenyloxy group having 2 to 5 carbon atoms; Z.sup.11 represents a single bond and Z.sup.12 represents CH.sub.2O, CF.sub.2O, CH.sub.2CH.sub.2, or a single bond; Ring A and Ring B each independently represent a trans-1,4-cyclohexylene group, a 1,4-phenylene group, or a 1,4-cyclohexenylene group; and m represents 1 and n represents 1, wherein the one or more fluorobenzene derivatives having a 1-propenyl group represented by general formula (I-1) includes a compound wherein m represenis 0 and n represents 1.

2. The liquid crystal composition according to claim 1, wherein the second component includes one or more compounds selected from the group of compounds represented by general formula (II-A) and/or general formula (II-B), ##STR00021## in the formulae, R.sup.i and R.sup.2 each independently represent an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, or an alkenyloxy group having 2 to 8 carbon atoms; one -CH.sub.2- or two or more non-adjacent - CH.sub.2- in R.sup.l and R.sup.2 may be each independently substituted with -0- and or -S-; one or more hydrogen atoms in R.sup.l and R.sup.2 may be each independently substituted with a fluorine atom or a chlorine atom; R.sup.l and R.sup.2 do not represent a 1-propenyl group; Ring A and Ring B each independently represent a trans-1,4-cyclohexylene group, a 1,4-phenylene group, a 2-fluoro-1,4- phenylene group, a 3-fluoro-1,4-phenylene group, a 3,5-difluoro-1,4-phenylene group, a 2,3- difluoro-1,4-phenylene group, a 1,4-cyclohexenylene group, a 1,4-bicyclooctylene group, a piperidine-1,4-diyl group, a naphthalene-2,6-diyl group, a decahydronaphthalene-2,6-diyl group, or a 1,2,3,4-tetrahydronaphthalene-2,6-diyl group; and p and q each independently represent 0, 1, or 2.

3. The liquid crystal composition according to claim 1, wherein a content of the first component is 3 mass % to 70 mass %.

4. The liquid crystal composition according to claim 1, wherein a content of the second component is 3 mass % to 70 mass %.

5. The liquid crystal composition according to claim 2, wherein the compounds represented by the general formula (II-A) are compounds represented by general formulae (II-A1) to (II-A5) and the compounds represented by the general formula (II-B) are compounds represented by general formulae (II-B1) to (II-B5), ##STR00022## in the formulae, R.sup.3 and R.sup.4 each independently represent an alkyl group having 1 to 8 carbon atoms or an alkenyl group having 2 to 8 carbon atoms; one or more hydrogen atoms in R.sup.3 and R.sup.4 may be each independently substituted with a fluorine atom; and R.sup.3 and R.sup.4 do not represent a 1-propenyl group.

6. The liquid crystal composition according to claim 1, comprising, as a third component, one or more compounds selected from the group of compounds represented by general formulae (III-A) to (III-J), ##STR00023## in the formulae, le represents an alkyl group having 1 to 5 carbon atoms or an alkenyl group having 2 to 5 carbon atoms, and R.sup.6 represents an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, or an alkenyloxy group having 2 to 5 carbon atoms.

7. The liquid crystal composition according to claim 1, comprising, as an additional component, one or more compounds represented by general formula (V), ##STR00024## in the formula, R.sup.21 and R.sup.22 each independently represent an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, or an alkenyloxy group having 2 to 8 carbon atoms.

8. The liquid crystal composition according to claim 7, wherein the compounds represented by the general formula (I-1), the general formula (II-A), the general formula (III-A), and the general formula (V) are contained at the same time, ##STR00025## in the formulae, R.sup.5 represents an alkyl group having 1 to 5 carbon atoms or an alkenyl group having 2 to 5 carbon atoms, and R.sup.6 represents an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, or an alkenyloxy group having 2 to 5 carbon atoms.

9. The liquid crystal composition according to claim 7, wherein the compounds represented by the general formula (I-1), the general formula (II-B), the general formula (III-A), and the general formula (V) are contained at the same time, ##STR00026## in the formulae, R.sup.5 represents an alkyl group having 1 to 5 carbon atoms or an alkenyl group having 2 to 5 carbon atoms, and R.sup.6 represents an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, or an alkenyloxy group having 2 to 5 carbon atoms.

10. The liquid crystal composition according to claim 7, wherein the compounds represented by the general formula (I-1), the general formula (II-A), the general formula (II-B), the general formula (III-A), and the general formula (V) are contained at the same time, ##STR00027## in the formulae, R.sup.5 represents an alkyl group having 1 to 5 carbon atoms or an alkenyl group having 2 to 5 carbon atoms, and R.sup.6 represents an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, or an alkenyloxy group having 2 to 5 carbon atoms.

11. The liquid crystal composition according to claim 1, comprising a polymerizable compound.

12. The liquid crystal composition according to claim 11, comprising, as the polymerizable compound, one or more compounds represented by general formula (IV), ##STR00028## in the formula, R.sup.7 and R.sup.8 each independently represent any of groups represented by formula (R-1) to formula (R-15) below, ##STR00029## ##STR00030## and X.sup.1 to X.sup.8 each independently represent a trifluoromethyl group, a trifluoromethoxy group, a fluorine atom, or a hydrogen atom.

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

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

15. A liquid crystal display device for a VA mode, a PSA mode, a PSVA mode, an IPS mode, or an ECB mode, the liquid crystal display device using the liquid crystal composition according to claim 1.

Description

DESCRIPTION OF EMBODIMENTS

(1) The liquid crystal composition of the present invention contains one or more fluorobenzene derivatives having a 1-propenyl group as a first component, and preferably contains 1 to 15 of the fluorobenzene derivatives and more preferably contains 2 to 10 of the fluorobenzene derivatives.

(2) The fluorobenzene derivative having a 1-propenyl group is specifically a compound in which a mesogenic skeleton having a 2,3-difluoro phenyl group has a 1-propenyl group as a terminal group, and preferably a compound represented by general formula (I).

(3) ##STR00006##
In the formula, R.sup.11 represents an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, or an alkenyloxy group having 2 to 8 carbon atoms. R.sup.11 preferably represents an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, or an alkenyloxy group having 2 to 5 carbon atoms. Z.sup.11 and Z.sup.12 each independently represent OCH.sub.2, CH.sub.2O, CF.sub.2O, OCF.sub.2, CH.sub.2CH.sub.2, CF.sub.2CF.sub.2, or a single bond, preferably each independently represent CH.sub.2O, CF.sub.2O, or a single bond, and more preferably each independently represent CH.sub.2O or a single bond. Ring A and Ring B each independently represent a trans-1,4-cyclohexylene group, a 1,4-phenylene group, a 2-fluoro-1,4-phenylene group, a 3-fluoro-1,4-phenylene group, a 3,5-difluoro-1,4-phenylene group, a 2,3-difluoro-1,4-phenylene group, a 1,4-cyclohexenylene group, a 1,4-bicyclo[2.2.2]octylene group, a piperidine-1,4-diyl group, a naphthalene-2,6-diyl group, a decahydronaphthalene-2,6-diyl group, or a 1,2,3,4-tetrahydronaphthalene-2,6-diyl group. Ring A and Ring B preferably each independently represent a trans-1,4-cyclohexylene group, a 1,4-phenylene group, a 2-fluoro-1,4-phenylene group, a 3-fluoro-1,4-phenylene group, a 3,5-difluoro-1,4-phenylene group, or a 2,3-difluoro-1,4-phenylene group and more preferably each independently represent a trans-1,4-cyclohexylene group or a 1,4-phenylene group. Furthermore, m and n each independently represent 0, 1, or 2 and preferably each independently represent 0 or 1, and m+n preferably represents 1 or 2.

(4) The content of the compounds represented by the general formula (I) is 3 mass % to 70 mass %, preferably 5 mass % to 50 mass %, and more preferably 10 mass % to 40 mass %.

(5) The compounds represented by the general formula (I) are, for example, preferably represented by general formula (I-A1), (I-B1), (I-C1), (I-D1), (I-E1), (I-A2), (I-B2), (I-C2), (I-D2), or (I-E2).

(6) ##STR00007## ##STR00008##

(7) In the formulae, R.sup.11 represents the same as above.

(8) The liquid crystal composition of the present invention contains one or more liquid crystal compounds having a negative dielectric anisotropy () with an absolute value of 3 or more as a second component, preferably contains liquid crystal compounds having a negative dielectric anisotropy () with an absolute value of 4 or more, and more preferably contains liquid crystal compounds having a negative dielectric anisotropy () with an absolute value of 5 or more. The dielectric anisotropy () of a liquid crystal compound is determined by extrapolating the measurement value of dielectric anisotropy () of a composition prepared by adding 10 mass % of the liquid crystal compound to a liquid crystal composition whose dielectric anisotropy at 25 C. is about 0.

(9) The second component preferably includes a compound selected from the group of compounds represented by general formula (II-A) and or general formula (II-B).

(10) ##STR00009##

(11) In the formulae, R.sup.1 and R.sup.2 each independently represent an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, or an alkenyloxy group having 2 to 8 carbon atoms; one CH.sub.2 or two or more non-adjacent CH.sub.2 in R.sup.1 and R.sup.2 may be each independently substituted with O and or S; one or more hydrogen atoms in R.sup.1 and R.sup.2 may be each independently substituted with a fluorine atom or a chlorine atom; and R.sup.1 and R.sup.2 do not represent a 1-propenyl group. R.sup.1 and R.sup.2 in the formulae preferably each independently represent a linear alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, or an alkenyloxy group having 2 to 5 carbon atoms. More specifically, R.sup.1 more preferably represents an alkenyl group having 2 to 5 carbon atoms to increase the elastic constant K.sub.33.

(12) Ring A and Ring B each independently represent a trans-1,4-cyclohexylene group, a 1,4-phenylene group, a 2-fluoro-1,4-phenylene group, a 3-fluoro-1,4-phenylene group, a 3,5-difluoro-1,4-phenylene group, a 2,3-difluoro-1,4-phenylene group, a 1,4-cyclohexenylene group, a 1,4-bicyclo[2.2.2]octylene group, a piperidine-1,4-diyl group, a naphthalene-2,6-diyl group, a decahydronaphthalene-2,6-diyl group, or a 1,2,3,4-tetrahydronaphthalene-2,6-diyl group. Ring A and Ring B preferably each independently represent a trans-1,4-cyclohexylene group, a 1,4-phenylene group, a 2-fluoro-1,4-phenylene group, a 3-fluoro-1,4-phenylene group, a 3,5-difluoro-1,4-phenylene group, or a 2,3-difluoro-1,4-phenylene group and more preferably each independently represent a trans-1,4-cyclohexylene group or a 1,4-phenylene group.

(13) Furthermore, p and q each independently represent 0, 1, or 2 and preferably each independently represent 0 or 1.

(14) More specifically, the general formula (II-A) preferably includes general formulae (II-A1) to (II-A5) and the general formula (II-B) preferably includes general formulae (II-B1) to (II-B5).

(15) ##STR00010## ##STR00011##

(16) In the formulae, R.sup.3 and R.sup.4 each independently represent an alkyl group having 1 to 8 carbon atoms or an alkenyl group having 2 to 8 carbon atoms; one or more hydrogen atoms in R.sup.3 and R.sup.4 may be each independently substituted with a fluorine atom; and R.sup.3 and R.sup.4 do not represent a 1-propenyl group. R.sup.3 and R.sup.4 in the formulae preferably each independently represent a linear alkyl group having 1 to 5 carbon atoms or an alkenyl group having 2 to 5 carbon atoms. More specifically, one of R.sup.3 and R.sup.4 more preferably represents an alkenyl group having 2 to 5 carbon atoms to increase the elastic constant K.sub.33.

(17) The liquid crystal composition of the present invention contains one or more of the second components, preferably contains 1 to 15 of the second components, and more preferably 2 to 10 of the second components.

(18) The content of the second component is 3 mass % to 70 mass %, preferably 5 mass % to 50 mass %, and more preferably 10 mass % to 40 mass %.

(19) The liquid crystal composition of the present invention may further contain one or more compounds selected from the group of compound represented by general formula (III-A) to general formula (III-J) as a third component, and preferably contains 1 to 10 compounds selected from the general formulae (III-A), (III-D), (III-F), (III-G), and (III-H).

(20) ##STR00012##

(21) In the formulae, R.sup.5 represents an alkyl group having 1 to 5 carbon atoms or an alkenyl group having 2 to 5 carbon atoms, and R.sup.6 represents an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, or an alkenyloxy group having 2 to 5 carbon atoms. In the compound represented by the general formula (III-A), R.sup.5 preferably represents an alkenyl group having 2 to 5 carbon atoms, and R.sup.6 preferably represents an alkyl group having 1 to 5 carbon atoms.

(22) One or more compounds represented by general formula (V) may be contained as an additional component.

(23) ##STR00013##

(24) In the formula, R.sup.21 and R.sup.22 each independently represent an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, or an alkenyloxy group having 2 to 8 carbon atoms. R.sup.21 and R.sup.22 preferably each independently represent an alkyl group having 1 to 5 carbon atoms or an alkenyl group having 2 to 5 carbon atoms.

(25) The liquid crystal composition of the present invention preferably contains the compounds represented by the general formula (I), the general formula (II-A1), and the general formula (II-A2) at the same time, more preferably contains the compounds represented by the general formula (I), the general formula (II-A1), the general formula (II-A2), and the general formula(III-A) at the same time, and further preferably contains the compounds represented by the general formula (I), the general formula (II-A1), the general formula (II-A2), the general formula (III-A), and the general formula (V) at the same time.

(26) The liquid crystal composition of the present invention preferably contains the compounds represented by the general formula (I), the general formula (II-B1), and the general formula (III-A) at the same time and more preferably contains the compounds represented by the general formula (I), the general formula (II-B1), the general formula (III-A), and the general formula (V) at the same time.

(27) The liquid crystal composition of the present invention preferably contains the compounds represented by the general formula (I), the general formula (II-A), and the general formula (II-B) at the same time. Specifically, the liquid crystal composition preferably contains the compounds represented by the general formula (I), the general formula (II-A1), the general formula (II-A2), and the general formula (II-B1) at the same time and more preferably contains the compounds represented by the general formula (I), the general formula (II-A1), the general formula (II-A2), the general formula (II-B1), the general formula (III-A), and the general formula (V) at the same time.

(28) In the liquid crystal composition of the present invention, the dielectric anisotropy () at 25 C. is 2.0 to 8.0, preferably 2.0 to 6.0, more preferably 2.0 to 5.0, and particularly preferably 2.5 to 4.0.

(29) In the liquid crystal composition of the present invention, the refractive index anisotropy (n) at 20 C. is 0.08 to 0.14, preferably 0.09 to 0.13, and more preferably 0.09 to 0.12. More specifically, n is preferably 0.10 to 0.13 when a small cell gap is employed and 0.08 to 0.10 when a large cell gap is employed.

(30) In the liquid crystal composition of the present invention, the viscosity (II) at 20 C. is 10 to 30 mPa.Math.s, preferably 10 to 25 mPa.Math.s, and more preferably 10 to 22 mPa.Math.s.

(31) In the liquid crystal composition of the present invention, the rotational viscosity (1) at 20 C. is 60 to 130 mPa.Math.s, preferably 60 to 110 mPa.Math.s, and more preferably 60 to 100 mPa.Math.s.

(32) In the liquid crystal composition of the present invention, the nematic phase-isotropic liquid phase transition temperature (T.sub.ni) is 60 C. to 120 C., preferably 70 C. to 100 C., and more preferably 70 C. to 85 C.

(33) In addition to the above compounds, the liquid crystal composition of the present invention may contain typical nematic liquid crystal, smectic liquid crystal, cholesteric liquid crystal, an antioxidant, an ultraviolet absorber, a polymerizable monomer, and the like.

(34) For example, a polymerizable compound such as a biphenyl derivative or a terphenyl derivative is contained as a polymerizable monomer, and the content of the polymerizable compound is preferably 0.01% to 2%.

(35) ##STR00014##
More specifically, the liquid crystal composition of the present invention preferably contains one or more polymerizable compounds represented by general formula (IV).

(36) In the formula, R.sup.7 and R.sup.8 each independently represent any of groups represented by formula (R-1) to formula (R-15) below.

(37) ##STR00015## ##STR00016##
X.sup.1 to X.sup.8 each independently represent a trifluoromethyl group, a trifluoromethoxy group, a fluorine atom, or a hydrogen atom.

(38) The biphenyl skeleton in the general formula (IV) is preferably selected from biphenyl skeletons represented by formula (IV-11) to formula (IV-14) and is more preferably a biphenyl skeleton represented by formula (IV-11).

(39) ##STR00017##

(40) Polymerizable compounds having the skeletons represented by the formula (IV-11) to the formula (IV-14) exhibit an optimum anchoring strength after being polymerized, and thus a good alignment state is achieved.

(41) A polymerizable compound-containing liquid crystal composition that contains the first component, the second component, the third component, and the polymerizable compound represented by the general formula (IV) in the present invention at the same time has a low viscosity (), a low rotational viscosity (1), and a high elastic constant (K.sub.33). Therefore, a PSA mode or PSVA mode liquid crystal display device that uses such a polymerizable compound-containing liquid crystal composition can achieve high-speed response.

(42) A liquid crystal display device that uses the liquid crystal composition of the present invention has a distinguished feature of high-speed response and is particularly useful as an active matrix driving liquid crystal display device. The liquid crystal display device is applicable to a VA mode, PSVA mode, PSA mode, IPS mode, or ECB mode liquid crystal display device.

EXAMPLES

(43) The present invention will now be further described in detail on the basis of Examples, but the present invention is not limited to Examples. In compositions of Examples and Comparative Examples below, % means mass %. In Examples, the following abbreviations are used for the description of compounds.

(44) TABLE-US-00001 (Side chain) -n C.sub.nH.sub.2n+1 linear alkyl group having n carbon atoms n- C.sub.nH.sub.2n+1 linear alkyl group having n carbon atoms On OC.sub.nH.sub.2n+1 linear alkoxy group having n carbon atoms nO C.sub.nH.sub.2n+1O linear alkoxy group having n carbon atoms V CHCH.sub.2 V CH.sub.2CH V1 CHCHCH.sub.3 1-propenyl group 1V CH.sub.3CHCH 1-propenyl group -2V CH.sub.2CH.sub.2CHCH.sub.3 V2- CH.sub.3CHCH.sub.2CH.sub.2 -2V1 CH.sub.2CH.sub.2CHCHCH.sub.3 1V2- CH.sub.3CHCHCH.sub.2CH.sub.2 (Linking group) -nO C.sub.nH.sub.2nO (Ring structure)

(45) ##STR00018##

(46) In Examples, the measured properties are as follows.

(47) T.sub.ni: nematic phase-isotropic liquid phase transition temperature ( C.)

(48) n: refractive index anisotropy at 20 C.

(49) : dielectric anisotropy at 25 C.

(50) : viscosity (mPa.Math.s) at 20 C.

(51) 1: rotational viscosity (mPa.Math.s) at 20 C.

(52) K.sub.33: elastic constant K.sub.33 (pN) at 20 C.

Comparative Examples 1 and 2 and Examples 1, 2, and 3

(53) LC-A (Comparative Example 1), LC-B (Comparative Example 2), LC-1 (Example 1), LC-2 (Example 2), and LC-3 (Example 3) each having a composition listed in Table 1 were prepared, and the physical properties were measured. The results are as follows.

(54) TABLE-US-00002 TABLE 1 Comparative Comparative Example Example Example Example 1 Example 2 1 2 3 LC-A LC-B LC-1 LC-2 LC-3 1V-Cy-1OPh5O2 General 11 12 12 formula (I) 1V-Cy-Cy-1OPh5O2 General 13 12 12 formula (I) 2-Cy-1OPh5O2 General 3 3 formula (II-A) 3-Cy-1OPh5O2 General 6 5 2 formula (II-A) 2-CyCy-1OPh5O2 General 10 7 13 4 4 formula (II-A) 3-CyCy-1OPh5O2 General 10 7 4 4 formula (II-A) 4-CyCy-1OPh5O2 General 10 7 formula (II-A) V-CyCy-1OPh5O2 General 10 5 formula (II-A) 3-CyPhPh5O2 General 4 formula (II-B) 3-CyCyV General 38 38 38 42 39 formula (III-A) 3-CyCyV1 General 4 3 formula (III-A) 3-PhPh-1 General 3 3 3 1.5 3 formula (III-F) 5-PhPh-1 General 2 2 1.5 formula (III-F) 3-PhPh5Ph-1 General 9 9 9 4 formula (V) 3-PhPh5Ph-2 General 9 9 9 4 formula (V) V2-PhPh5Ph-2V General 10 12 formula (V) 1V2-PhPh5Ph-2V1 General 5 formula (V) Total 100 100 100 100 100 Tni [ C.] 76.1 76.3 76.0 76.2 76.4 n 0.108 0.109 0.108 0.108 0.109 [mPa .Math. s] 14.6 14.5 14.1 13.7 13.9 1 [mPa .Math. s] 98 99 99 96 95 3.2 3.1 3.2 3.1 3.2 K.sub.33 [pN] 13.9 14.2 16.0 15.8 16.1 1/K.sub.33 7.1 7.0 6.2 6.1 5.9

(55) The liquid crystal compositions LC-1, LC-2, and LC-3 of the present invention had a low viscosity (11), a low rotational viscosity (1), and a considerably high elastic constant (K.sub.33). Therefore, 1/K.sub.33 of LC-1, LC-2, and LC-3 were 6.2, 6.1, and 5.9, respectively, which were much lower than those of LC-A and LC-B of Comparative Examples. The response speed of each of liquid crystal display devices including the liquid crystal compositions was measured. The liquid crystal display devices including LC-1, LC-2, and LC-3 had a sufficiently high response speed, which was higher than the response speed of LC-A and LC-B by 10% or more. Furthermore, the voltage holding ratio (VHR) was measured, and it was confirmed that high VHR was achieved. The cell thickness was 3.5 m and the alignment film was JALS2096. The response speed was measured at 20 C. using DMS301 manufactured by AUTRONIC-MELCHERS with Von of 5.5 V and Voff of 1.0 V. The VHR was measured using VHR-1 manufactured by TOYO Corporation at a voltage of 5 V at a frequency of 60 Hz at a temperature of 60 C. Although the conditions of injection into liquid crystal cells (pressure and the ODF method) were changed, the physical properties did not change.

Comparative Example 3 and Example 4

(56) LC-C (Comparative Example 3) and LC-4 (Example 4) each having a composition listed in Table 2 were prepared, and the physical properties were measured. The results are as follows.

(57) TABLE-US-00003 TABLE 2 Comparative Example 3 Example 4 LC-C LC-4 1V-CyPh5-2 General 4 formula (I) 1V-Cy-1OPh5O2 General 7 formula (I) 1V-CyCyPh5-1 General 4 formula (I) 1V-CyCy-1OPh5O2 General 7 formula (I) 3-Cy-1OPh5O1 General 5 formula (II-A) 3-CyCy-1OPh5O2 General 10 3 formula (II-A) V-CyCy-1OPh5O2 General 10 8 formula (II-A) 3-CyPh5-2 General 4 formula (II-B) 3-CyCyPh5-1 General 4 formula (II-B) 3-CyCyV General 37 37 formula (III-A) 3-CyCy-2 General 3 formula (III-A) 5-PhPh-1 General 8 5 formula (III-F) 3-PhPh5Ph-1 General 8 8 formula (V) 3-PhPh5Ph-2 General 11 11 formula (V) 3-PhPh5Ph-3 General 3 3 formula (V) Total 100 100 Tni [ C.] 72.3 73.1 n 0.114 0.114 [mPa .Math. s] 13.9 13.5 1 [mPa .Math. s] 90 88 2.7 2.7 K.sub.33 [pN] 13.2 14.4 1/K.sub.33 6.8 6.1

(58) The liquid crystal composition LC-4 of the present invention had a low viscosity (), a low rotational viscosity (1), and a high elastic constant (K.sub.33). Therefore, 1/K.sub.33 of LC-4 was 6.1, which was much lower than that of LC-C of Comparative Example. The response speed of each of liquid crystal display devices including the liquid crystal compositions was measured. The liquid crystal display device including LC-4 had a higher response speed than the liquid crystal display device including LC-C. Furthermore, the voltage holding ratio (VHR) was measured, and it was confirmed that high VHR was achieved. The cell thickness was 3.5 m and the alignment film was JALS2096. The response speed was measured at 20 C. using DMS301 manufactured by AUTRONIC-MELCHERS with Von of 5.5 V and Voff of 1.0 V. The VHR was measured using VHR-1 manufactured by TOYO Corporation at a voltage of 5 V at a frequency of 60 Hz at a temperature of 60 C. Although the conditions of injection into liquid crystal cells (pressure and the ODF method) were changed, the physical properties did not change.

Comparative Example 4 and Example 5

(59) LC-D (Comparative Example 4) and LC-5 (Example 5) each having a composition listed in Table 3 were prepared, and the physical properties were measured. The results are as follows.

(60) TABLE-US-00004 TABLE 3 Comparative Example 4 Example 5 LC-D LC-5 1V-CyPh5-2 General 7 formula (I) 1V-CyCyPh5-1 General 7 formula (I) 3-CyPh5O2 General 12 5 formula (II-B) 3-PhPh5O2 General 10 10 formula (II-B) 3-CyCyPh5O2 General 11 4 formula (II-B) 2-CyPhPh5O2 General 7 7 formula (II-B) 3-CyPhPh5O4 General 7 7 formula (II-B) 4-CyPhPh5O3 General 6 6 formula (II-B) 3-CyCy-2 General 19 23 formula (III-A) 3-CyCy-4 General 6 4 formula (III-A) 3-CyCy-5 General 6 4 formula (III-A) 3-CyCyV1 General 10 10 formula (III-A) 3-CyCyPh-1 General 6 6 formula (III-G) Total 100 100 Tni [ C.] 76.3 76.5 n 0.093 0.095 [mPa .Math. s] 16.7 16.8 1 [mPa .Math. s] 101 99 2.8 2.8 K.sub.33 [pN] 13.5 14.4 1/K.sub.33 7.5 6.7

(61) The liquid crystal composition LC-5 of the present invention had a low viscosity (), a low rotational viscosity (1), and a high elastic constant (K.sub.33). Therefore, 1/K.sub.33 of LC-5 was 6.7, which was much lower than that of LC-D of Comparative Example. The response speed of each of liquid crystal display devices including the liquid crystal compositions was measured. The liquid crystal display device including LC-5 had a higher response speed than the liquid crystal display device including LC-D. Furthermore, the voltage holding ratio (VHR) was measured, and it was confirmed that high VHR was achieved. The cell thickness was 3.5 m and the alignment film was JALS2096. The response speed was measured at 20 C. using DMS301 manufactured by AUTRONIC-MELCHERS with Von of 5.5 V and Voff of 1.0 V. The VHR was measured using VHR-1 manufactured by TOYO Corporation at a voltage of 5 V at a frequency of 60 Hz at a temperature of 60 C. Although the conditions of injection into liquid crystal cells (pressure and the ODF method) were changed, the physical properties did not change. It was confirmed from the above results that the liquid crystal composition of the present invention had sufficiently low a sufficiently low rotational viscosity 1, a high elastic constant K.sub.33, and a negative dielectric anisotropy () with a high absolute value without decreasing n and T.sub.ni, and a VA mode liquid crystal display device that uses the liquid crystal composition had high display quality and high response speed.