Nematic liquid crystal composition and liquid crystal display device

Abstract

The present invention provides a liquid crystal composition having a sufficiently low viscosity (), 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 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 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: 3 mass % to 25 mass % of a first component comprising one or more compounds represented by general formula (I), ##STR00017## (in the formula, R.sup.11 represents an alkenyl group having 2 to 8 carbon atoms, and R.sup.12 represents an alkenyl group having 2 to 8 carbon atoms), and a second component comprising one or more liquid crystal compounds, each having a negative with an absolute value of 3 or more.

2. The liquid crystal composition according to claim 1, wherein the liquid crystal composition has a dielectric anisotropy () of 2.0 to 8.0 at 25 C., a refractive index anisotropy (n) of 0.08 to 0.14 at 20 C., a viscosity () of 10 to 30 mPa.Math.s at 20 C., a rotational viscosity 1 of 60 to 130 mPa.Math.s at 20 C., and a nematic phase-isotropic liquid phase transition temperature (T.sub.ni) of 60 C. to 120 C.

3. The liquid crystal composition according to claim 1, wherein the second component are one or more compounds selected from the group consisting of compounds represented by general formulae (II-A) and (II-B), ##STR00018## (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 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; a ring A and a 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; and p and q each independently represent 0, 1, or 2).

4. The liquid crystal composition according to claim 1, wherein a content of the second component is 10 mass % to 90 mass %.

5. The liquid crystal composition according to claim 3, wherein the second component are one or more compounds selected from the group consisting of compounds represented by general formulae (II-A1), (II-A2), and (II-B1), ##STR00019## (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, and one or more hydrogen atoms in R.sup.3 and R.sup.4 may be each independently substituted with a fluorine atom).

6. The liquid crystal composition according to claim 1, comprising, as a third component, one or more compounds selected from the group consisting of compounds represented by general formulae (III-A) to (III-J), ##STR00020## (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).

7. The liquid crystal composition according to claim 5, wherein the second component comprises two liquid crystal compounds, each represented by the general formula (II-A1), and the general formula (II-A2), respectively.

8. The liquid crystal composition according to claim 5, wherein the second component comprises two liquid crystal compounds, each represented by the general formula (II-A1), the general formula (II-A2), and wherein the liquid crystal composition further comprises a third component represented by a general formula (III-A), ##STR00021## (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 5, wherein the second component comprises three liquid crystal compounds, each represented by the general formula (II-A1), the general formula (II-A2), the general formula (II-B1), and wherein the liquid crystal composition further comprises a third component represented by a general formula (III-A), ##STR00022## (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 1, further comprising one or more compounds represented by general formula (V), ##STR00023## (in the formula, R.sup.21 and R.sup.22 each independently represent an alkyl group having 1 to 8 carbon atoms or an alkoxy group having 1 to 8 carbon atoms).

11. The liquid crystal composition according to claim 10, wherein the second component comprises two liquid crystal compounds, each represented by a general formula (II-A1), and a general formula (II-A2), respectively, ##STR00024## (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, and one or more hydrogen atoms in R.sup.3 and R.sup.4 may be each independently substituted with a fluorine atom); wherein the liquid crystal composition further comprises a general formula (III-A)), ##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).

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

13. The liquid crystal composition according to claim 12, further comprising, as the polymerizable compound, one or more polymerizable monomers represented by general formula (IV), ##STR00026## (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, ##STR00027## and X.sup.1 to X.sup.8 each independently represent a trifluoromethyl group, a trifluoromethoxy group, a fluorine atom, or a hydrogen atom).

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 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

EXAMPLES

(1) 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 %.

(2) In Examples, the following abbreviations are used for the description of compounds.

(3) (Side Chain)

(4) -n CH.sub.2n+1 linear alkyl group having n carbon atoms

(5) n- C.sub.nH.sub.2n+1 linear alkyl group having n carbon atoms

(6) On OC.sub.nH.sub.2n+1 linear alkoxy group having n carbon atoms

(7) nO C.sub.nH.sub.2+1O linear alkoxy group having n carbon atoms

(8) V CHCH.sub.2

(9) V CH.sub.2CH

(10) V1 CHCHCH.sub.3

(11) 1V CH.sub.3CHCH

(12) -2V CH.sub.2CH.sub.2CHCH.sub.2

(13) V2- CH.sub.2CHCH.sub.2CH.sub.2

(14) -2V1 CH.sub.2CH.sub.2CHCHCH.sub.3

(15) 1V2- CH.sub.3CHCHCH.sub.2CH.sub.2

(16) -T- CC

(17) (Ring Structure)

(18) ##STR00016##

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

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

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

(22) : dielectric anisotropy at 25 C.

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

(24) 1: rotational viscosity (mPa.Math.s) at 20 C.

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

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

(26) 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.

(27) TABLE-US-00001 TABLE 1 Comparative Comparative Example Example Example Example 1 Example 2 1 2 3 LC-A LC-B LC-1 LC-2 LC-3 3-PhPh-1 General for- 7 mula (III-F) V2PhTPh2V 17 V2PhPh5Ph2V General for- 12 13 14 mula (I-A1) 1V2PhPh5Ph2V1 General for- 10 mula (I-A2) 3-Cy-Cy-V General for- 36 37 41 38 36 mula (III-A) 3-Cy-Cy-V1 General for- 4 6 mula (III-A) 3-Cy-1OPh5O2 General for- 9 8 8 9 8 mula (II-A1) 1V-Cy-1OPh5O2 General for- 7 9 8 mula (II-A1) 2-Cy-Cy-1OPh5O2 General for- 13 13 4 mula (II-A2) 3-Cy-Cy-1OPh5O2 General for- 13 13 12 4 8 mula (II-A2) V-Cy-Cy-1OPh5O2 General for- 4 9 5 6 mula (II-A2) 1V-Cy-Cy-1OPh5O2 General for- 12 4 6 mula (II-A2) 3-PhPh5Ph-1 General for- 9 4 mula (V) 3-PhPh5Ph-2 General for- 9 11 4 mula (V) Total 100 100 100 100 100 T.sub.ni [ C.] 75.3 76.0 75.3 76.0 76.2 n 0.110 0.110 0.110 0.110 0.110 [mPa .Math. s] 15.2 13.3 12.6 12.3 12.6 1 [mPa .Math. s] 102 97 87 85 88 3.3 3.2 3.2 3.1 3.2 K.sub.33 [pN] 14.2 13.9 14.8 15.1 15.3 1/K.sub.33 7.2 7.0 5.9 5.6 5.8

(28) The liquid crystal compositions LC-1, LC-2, and LC-3 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-1, LC-2, and LC-3 were 5.9, 5.6, and 5.8, 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 of 3.2 to 3.5 msec whereas the liquid crystal display devices including LC-A and LC-B had a response speed of 4.2 msec and 4.1 msec, respectively. 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.

(29) 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

(30) 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.

(31) TABLE-US-00002 TABLE 2 Comparative Example Example 4 3 LC-C LC-4 3-PhPh-1 General 10 formula (III-F) 1V2PhPh5 General 18 Ph2V1 formula (I-A2) 3-Cy-Cy-V General 33 38 formula (III-A) 3-Cy-Cy-V1 General 3 formula (III-A) 3-Cy-1OPh5O2 General 9 9 formula (II-A1) 1V-Cy-1O General 10 Ph5O2 formula (II-A1) 2-Cy-Cy-1O General 13 Ph5O2 formula (II-A2) 3-Cy-Cy-1O General 13 8 Ph5O2 formula (II-A2) 4-Cy-Cy-1O General 4 Ph5O2 formula (II-A2) V-Cy-Cy-1O General 7 Ph5O2 formula (II-A2) 1V-Cy-Cy- General 1OPh5O2 formula (II-A2) 3-PhPh5Ph-1 General formula (V) 4 4 3-PhPh5Ph-2 General formula (V) 14 3 Total 100 100 T.sub.ni [ C.] 71.8 72.6 n 0.112 0.112 [mPa .Math. s] 15.1 13.1 1 [mPa .Math. s] 102 90 3.15 3.18 K.sub.33 [pN] 14.3 15.2 1/K.sub.33 7.1 5.9

(32) 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 5.9, 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 sufficiently high response speed of 3.6 msec whereas the liquid crystal display device including LC-C had a response speed of 4.3 msec. 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.

(33) 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 Examples 5, 6, and 7

(34) LC-D (Comparative Example 4), LC-5 (Example 5), LC-6 (Example 6), and LC-7 (Example 7) each having a composition listed in Table 3 were prepared, and the physical properties were measured. The results are as follows.

(35) TABLE-US-00003 TABLE 3 Comparative Example Example Example Example 4 5 6 7 LC-D LC-5 LC-6 LC-7 3-PhPh-1 General formula (III-F) 10 3 V2PhPh5Ph2V General formula (I-A1) 12 12 14 1V2PhPh5Ph2V1 General formula (I-A2) 7 9 3-Cy-Cy-V General formula (III-A) 34 36 39 39 3-Cy-Cy-V1 General formula (III-A) 3 5 3 3 3-Cy-1OPh5O2 General formula (II-A1) 7 6 8 8 1V-Cy-1OPh5O2 General formula (II-A1) 6 7 8 2-Cy-Cy-1OPh5O2 General formula (II-A2) 7 3-Cy-Cy-1OPh5O2 General formula (II-A2) 10 7 6 3 4-Cy-Cy-1OPh5O2 General formula (II-A2) 5 1V-Cy-Cy-1OPh5O2 General formula (II-A2) 7 6 3 2-Cy-PhPh5O2 General formula (II-B1) 4 3-Cy-PhPh5O3 General formula (II-B1) 3 3-PhPh5Ph-1 General formula (V) 9 6 3-PhPh5Ph-2 General formula (V) 15 12 12 6 Total 100 100 100 100 T.sub.ni [ C.] 72.2 72.7 73.4 73.8 n 0.121 0.1220 0.1210 0.1230 [mPa .Math. s] 14.0 12.5 12.3 12.5 1 [mPa .Math. s] 98 83 84 84 2.59 2.52 2.54 2.58 K.sub.33 [pN] 13.1 14.1 13.9 14.3 1/K.sub.33 7.5 5.9 6.0 5.9

(36) The liquid crystal compositions LC-5, LC-6, and LC-7 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, LC-6, and LC-7 were much lower than that of LC-D of Comparative Example.

Comparative Example 5 and Example 8

(37) LC-E (Comparative Example 5) and LC-8 (Example 8) each having a composition listed in Table 4 were prepared, and the physical properties were measured. The results are as follows.

(38) TABLE-US-00004 TABLE 4 Comparative Exam- Example 5 ple 8 LC-E LC-8 3-PhPh-1 General formula (III-F) 6 V2PhPh5 General formula (I-A1) 15 Ph2V 3-Cy-Cy-V General formula (III-A) 36 40 3-Cy-Cy-V1 General formula (III-A) 5 3-Cy-Cy-Ph-1 General formula (III-G) 6 3-Cy-1OPh5O2 General formula (II-A1) 9 4 1V-Cy-1O General formula (II-A1) 7 Ph5O2 2-Cy-Cy-1O General formula (II-A2) 13 10 Ph5O2 3-Cy-Cy-1O General formula (II-A2) 13 10 Ph5O2 4-Cy-Cy-1O General formula (II-A2) 7 Ph5O2 V-Cy-Cy-1O General formula (II-A2) 9 Ph5O2 3-PhPh5Ph-1 General formula (V) 5 3-PhPh5Ph-2 General formula (V) 5 Total 100 100 T.sub.ni [ C.] 79.3 80.1 n 0.098 0.098 [mPa .Math. s] 14.2 13.2 1 [mPa .Math. s] 97 84 3.1 3.2 K.sub.33 [pN] 13.9 14.8 1/K.sub.33 7.0 5.7

(39) The liquid crystal composition LC-8 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-8 was 5.7, which was much lower than that of LC-E of Comparative Example.

(40) It was confirmed from the above results that the liquid crystal composition of the present invention had a 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.