Liquid crystal composition and liquid crystal display device comprising same

Abstract

The present invention provides a liquid crystal composition and a liquid crystal display device thereof. The liquid crystal composition comprises at least one compound of general formula I and at least one compound of general formula II. The liquid crystal composition has a larger vertical dielectric constant (?.sub.?), a larger ratio of the vertical dielectric constant to the absolute value of dielectric anisotropy (?.sub.?/|??|), a larger K.sub.ave value and a higher transmittance while maintaining an appropriate clearing point, an appropriate optical anisotropy, and an appropriate absolute value of the dielectric anisotropy, such that the liquid crystal display device comprising the same has a better contrast, a faster response speed and a better transmittance while maintaining an appropriate range of operating temperature and an appropriate threshold voltage. ##STR00001##

Claims

1. A liquid crystal composition comprising: at least one compound of general formula I: ##STR00067## at least one compound of general formula II: ##STR00068## wherein, R.sub.1 represents C.sub.2-11 linear or C.sub.3-11 branched alkenoxy; R.sub.2 represents C.sub.1-12 linear or C.sub.3-12 branched alkyl, ##STR00069## one or more than two nonadjacent CH.sub.2 in the C.sub.1-12 linear or C.sub.3-12 branched alkyl can each be independently replaced by CH?CH, C?C, O, CO, COO or OCO; R.sub.3 and R.sub.4 each independently represents C.sub.1-11 linear or C.sub.3-11 branched alkoxy; L.sub.1, L.sub.2, L.sub.3 and L.sub.4 each independently represents F, Cl, CF.sub.3, OCF.sub.3 or CHF.sub.2; and n.sub.1 represents 0 or 1.

2. The liquid crystal composition according to claim 1, wherein the liquid crystal composition comprises at least two compounds of general formula II.

3. The liquid crystal composition according to claim 2, wherein the liquid crystal composition comprises at least one compound of general formula II in which n.sub.1 represents 1.

4. The liquid crystal composition according to claim 1, wherein the liquid crystal composition further comprises at least one compound of general formula M: ##STR00070## wherein, R.sub.M1 and R.sub.M2 each independently represents C.sub.1-12 linear or C.sub.3-12 branched alkyl, ##STR00071## one or more than two nonadjacent CH.sub.2 in the C.sub.1-12 linear or C.sub.3-12 branched alkyl can each be independently replaced by CH?CH, C?C, O, CO, COO or OCO; ring ##STR00072## ring ##STR00073## and ring ##STR00074## each independently represents ##STR00075## wherein one or more CH.sub.2 in ##STR00076## can be replaced by O, and one or more single bond in the ring can be replaced by double bond, and at most one H on ##STR00077## can be substituted by halogen, Z.sub.M1 and Z.sub.M2 each independently represents single bond, COO, OCO, CH.sub.2O, OCH.sub.2, C?C, CH?CH, CH.sub.2CH.sub.2 or (CH.sub.2).sub.4; and n.sub.M represents 0, 1 or 2, wherein, when n.sub.M=2, ring ##STR00078## can be same or different, and Z.sub.M2 can be same or different.

5. The liquid crystal composition according to claim 4, wherein the liquid crystal composition further comprises at least one compound of general formula III: ##STR00079## wherein, R.sub.5 and R.sub.6 each independently represents C.sub.1-12 linear or branched alkyl, ##STR00080## one or more than two nonadjacent CH.sub.2 in the C.sub.1-12 linear or C.sub.3-12 branched alkyl can each be independently replaced by CH?CH, C?C, O, CO, COO or OCO; T.sub.1, T.sub.2, T.sub.3, T.sub.4, T.sub.5 and T.sub.6 each independently represents H, C.sub.1-3 alkyl or halogen; and the compound of general formula III comprises at least one ring structure ##STR00081##

6. The liquid crystal composition according to claim 5, wherein the compound of general formula I provides 0.1-50 wt. % of the total weight of the liquid crystal composition; the compound of general formula II provides 0.1-60 wt. % of the total weight of the liquid crystal composition; the compound of general formula M provides 1-80 wt. % of the total weight of the liquid crystal composition; and the compound of general formula III provides 0.1-30 wt. % of the total weight of the liquid crystal composition.

7. The liquid crystal composition according to claim 1, wherein the liquid crystal composition further comprises at least one compound of general formula N: ##STR00082## wherein, R.sub.N1 and R.sub.N2 each independently represents C.sub.1-12 linear or branched alkyl, ##STR00083## one or more than two nonadjacent CH.sub.2 in the C.sub.1-12 linear or C.sub.1-12 branched C.sub.3-12 alkyl can each be independently replaced by CH?CH, C?C, O, CO, COO or OCO; ring ##STR00084## and ring ##STR00085## each independently represents ##STR00086## wherein one or more CH.sub.2 in ##STR00087## can be replaced by O, one or more single bond in the ring can be replaced by double bond, wherein one or more H on ##STR00088## can each be independently substituted by F, Cl or CN, and one or more CH? within the ring can be replaced by N?; Z.sub.N1 and Z.sub.N2 each independently represents single bond, COO, OCO, CH.sub.2O, OCH.sub.2, CH?CH, C?C, CH.sub.2CH.sub.2, CF.sub.2CF.sub.2, (CH.sub.2).sub.4, CF.sub.2O or OCF.sub.2; L.sub.N1 and L.sub.N2 each independently represents F, Cl, CF.sub.3, OCF.sub.3 or CHF.sub.2; L.sub.N3 and L.sub.N4 each independently represents H, C.sub.1-3 alkyl or halogen; nN.sub.1 represents 0, 1, 2 or 3, n.sub.N2 represents 0 or 1, and 0?n.sub.N1+n.sub.N2?3, wherein when n.sub.N1=2 or 3, ring ##STR00089## can be same or different and Z.sub.N1 Can be same or different; when n.sub.N1+n.sub.N2=0, or n.sub.N1+n.sub.N2=1, and the compound of general formula N comprises biphenyl structure, R.sub.N1 and R.sub.N2 are not alkoxy; when n.sub.N1 represents 2, n.sub.N2 represents 0, and the compound of general formula N comprises biphenyl structure, R.sub.N1 is not alkenyl or alkenoxy; and when n.sub.N1+n.sub.N2=3, the compound of general formula N does not comprise terphenyl structure.

8. A liquid crystal display device comprising the liquid crystal composition of claim 1.

9. The liquid crystal composition according to claim 4, wherein the compound of general formula M is selected from a group consisting of the following compounds: ##STR00090## ##STR00091## ##STR00092## wherein, R.sub.M1 and R.sub.M2 each independently represents C.sub.1-12 linear or C.sub.3-12 branched alkyl, ##STR00093## one or more than two nonadjacent CH.sub.2 in the C.sub.1-12 linear or C.sub.3-12 branched alkyl can each be independently replaced by CH=CH, C?C,O,COCOO or OCO; ring ##STR00094## ring ##STR00095## and ring ##STR00096## each independently represents ##STR00097## wherein one or more CH.sub.2 in ##STR00098## can be replaced by O, and one or more single bond in the ring can be replaced by double bond, and at most one H on ##STR00099## can be substituted by halogen.

10. The liquid crystal composition according to claim 5, wherein the compound of general formula III is selected from a group consisting of the following compounds: ##STR00100## wherein R.sub.5 and R.sub.6 each independently represents C.sub.1-12 linear or C.sub.3-12 branched alkyl, ##STR00101## one or more than two nonadjacent CH.sub.2 in the C.sub.1-12 linear or C.sub.3-12 branched alkyl can each be independently replaced by CH=CH, C?C, O, CO, COO or OCO.

11. The liquid crystal composition according to claim 7, wherein the compound of general formula N is selected from a group consisting of the following compounds: ##STR00102## ##STR00103## ##STR00104## ##STR00105## wherein, R.sub.N1 and R.sub.N2 each independently represents C.sub.1-12 linear or C.sub.3-12 branched alkyl, ##STR00106## one or more than two nonadjacent CH.sub.2in the C.sub.1-12 linear or C.sub.3-12 branched C.sub.3-12 alkyl can each be independently replaced by CH=CH, C?C, O,CO, COOor OCO; R.sub.N1 and R.sub.N2 each independently represents C.sub.1-8 linear or C.sub.3-8 branched alkyl, or C.sub.2-8 linear or C.sub.3-8 branched alkenyl; and R.sub.N1 represents C.sub.1-8 linear or C.sub.3-8 branched alkyl, or C.sub.1-7 linear or C.sub.3-7 branched alkoxy.

12. The liquid crystal composition according to claim 11, wherein the compound of general formula N provides 0.1-60 wt. %.

Description

DETAILED EMBODIMENTS

(1) The present invention will be illustrated by combining the detailed embodiments below. It should be noted that, the following examples are exemplary embodiments of the present invention, which are only used to illustrate the present invention, not to limit it. Other combinations and various modifications within the conception of the present invention are possible without departing from the subject matter and scope of the present invention.

(2) For the convenience of the expression, the group structures of the compounds in the following Examples are represented by the codes listed in Table 2:

(3) TABLE-US-00002 TABLE 2 Codes of the group structures of the compounds Unit structure of group Code Name of group C 1,4-cyclohexylidene P 1,4-phenylene G 2-fluoro-1,4-phenylene W 2,3-difluoro-1,4-phenylene F F fluorine substituent O O oxygen bridge group CH.sub.2O 1O methyleneoxy CH?CH or CH?CH.sub.2 V ethenyl CH.sub.2CH.sub.2 2 ethyl bridge group C.sub.nH.sub.2n+1 or C.sub.nH.sub.2n n (n alkyl or alkylene represents an integer of 1-12)

(4) Take the compound with following structural formula as an example:

(5) ##STR00066## represented by the codes listed in Table 2, this structural formula can be expressed as nCCGF, in which, n in the code represents the number of the carbon atoms of the alkyl on the left, for example, n is 3, meaning that the alkyl is C.sub.3H.sub.7; C in the code represents 1,4-cyclohexylidene, G represents 2-fluoro-1,4-phenylene, and F represents fluoro.

(6) The abbreviated codes of the test items in the following Examples are as follows: Cp clearing point (nematic-isotropy phases transition temperature, ? C.) ?n optical anisotropy (589 nm, 25? C.) ?.sub.? vertical dielectric constant ?? dielectric anisotropy (1 KHz, 25? C.) ?.sub.?/|??| ratio of the vertical dielectric constant to the absolute value of dielectric anisotropy K.sub.ave average elastic constant (20? C.) T.sub.r transmittance (%) (20? C.) wherein, Cp: tested by melting point apparatus. ?n: tested using an Abbe Refractometer under a sodium lamp (589 nm) light source at 25? C. ??: ??=?i??.sub.?; in which, ?i is the dielectric constant parallel to the molecular axis, ?.sub.? is the dielectric constant perpendicular to the molecular axis, test conditions: 25? C., 1 KHz, VA-type test cell with a cell gap of 6 ?m.

(7) T.sub.r: the V-T profile of the optic-tunable device is measured using a DMS 505 tester for optical-electro comprehensive performance test, and the maximum value of the transmittance in the V-T profile is taken as the transmittance of the liquid crystal, in which the test cell is a negative IPS mode cell with a cell gap of 3.5 ?m. K.sub.ave: K.sub.ave=1/3 (K.sub.11+K.sub.22+K.sub.33), in which K.sub.11, K.sub.22 and K.sub.33 are calculated through the C-V curves of the liquid crystal material tested by LCR meter and VA-type test cell; test conditions: 20? C., VA-type test cell with a cell gap of 6 ?m, V=0.1?20 V.

(8) The components used in the following Examples can either be synthesized by method known in the art or be obtained commercially. The synthetic techniques are conventional, and each of the obtained liquid crystal compounds is tested to meet the standards of electronic compound.

(9) The liquid crystal compositions are prepared in accordance with the ratios specified in the following Examples. The preparation of the liquid crystal compositions is proceeded by mixing in accordance with the ratios through conventional methods in the art, such as heating, ultrasonic wave, suspension and the like.

Comparative Example 1

(10) The liquid crystal composition of Comparative Example 1 is prepared according to each compound and weight percentage listed in Table 3 and is tested by filling the same between two substrates of a liquid crystal display device.

(11) TABLE-US-00003 TABLE 3 Formulation and test performances of liquid crystal composition Weight Code of Test results for the Code of component percent structure performance parameters 3CWO2 10 N-2 Cp 80 3CWO4 8 N-2 ?n 0.105 3CCWO2 10 N-5 ?.sub.? 5.8 3CCWO3 9 N-5 ?? ?4.3 1VCPWO2 7 I-2 K.sub.ave 12.7 3CPWO4 7 N-11 T.sub.r 13.2 3CPO2 6 M-2 ?.sub.?/|??| 1.35 3CPP2 10 M-16 3CC2 7 M-1 3CCV 20 M-1 3CCV1 6 M-1 Total 100

Example 1

(12) The liquid crystal composition of Example 1 is prepared according to each compound and weight percentage listed in Table 4 and is tested by filling the same between two substrates of a liquid crystal display device.

(13) TABLE-US-00004 TABLE 4 Formulation and test performances of liquid crystal composition Weight Code of Test results for the Code of component percent structure performance parameters 3CWO2 8 N-2 Cp 81 3CCWO2 10 N-5 ?n 0.108 3CCWO3 9 N-5 ?.sub.? 7.3 1VCPWO2 7 I-2 ?? ?4.4 3CPWO4 7 N-11 K.sub.ave 13.9 3CPO2 6 M-2 T.sub.r 13.8 3CPP2 10 M-16 ?.sub.?/|??| 1.66 3CC2 7 M-1 3CCV 20 M-1 3CCV1 6 M-1 3OWO2 5 II 2OPWO2 5 II Total 100

(14) It can be seen from the comparison between Comparative Example 1 and Example 1 that the liquid crystal composition comprising the compound of general formula I and the compound of general formula II of the present invention has a larger vertical dielectric constant (?.sub.?), a larger ratio of the vertical dielectric constant to the absolute value of dielectric anisotropy (?.sub.?/|??|), a larger K.sub.ave value and a higher transmittance in view of the liquid crystal composition comprising only the compound of general formula I of the present invention, while maintaining an appropriate clearing point, an appropriate optical anisotropy, and an appropriate absolute value of the dielectric anisotropy.

Comparative Example 2

(15) The liquid crystal composition of Comparative Example 2 is prepared according English Translation of PCT Application for 2690-37 PCTXUS to each compound and weight percentage listed in Table 5 and is tested by filling the same between two substrates of a liquid crystal display device.

(16) TABLE-US-00005 TABLE 5 Formulation and test performances of liquid crystal composition Weight Code of Test results for the Code of component percent structure performance parameters 3CWO2 10 N-2 Cp 79 3CCWO2 7 N-5 ?n 0.106 3CCWO3 7 N-5 ?.sub.? 6.2 3CPWO2 6 N-11 ?? ?4.2 3CPWO4 6 N-11 K.sub.ave 12.4 3CPO2 6 M-2 T.sub.r 12.9 3CPP2 5 M-16 ?.sub.?/|??| 1.48 3CC2 7 M-1 3CCV 20 M-1 3CCV1 6 M-1 5OWO3 7 II 2OPWO2 8 II 3PWP4 5 III-2 Total 100

Example 2

(17) The liquid crystal composition of Example 2 is prepared according to each compound and weight percentage listed in Table 6 and is tested by filling the same between two substrates of a liquid crystal display device.

(18) TABLE-US-00006 TABLE 6 Formulation and test performances of liquid crystal composition Weight Code of Test results for the Code of component percent structure performance parameters 3CWO2 10 N-2 Cp 76 3CCWO2 7 N-5 ?n 0.107 3CCWO3 7 N-5 ?.sub.? 7.4 1VCPWO2 6 I-2 ?? ?4.5 3VCPWO4 6 I-2 K.sub.ave 13.9 3CPO2 6 M-2 T.sub.r 14.2 3CPP2 5 M-16 ?.sub.?/|??| 1.64 3CC2 7 M-1 3CCV 20 M-1 3CCV1 6 M-1 5OWO3 7 II 2OPWO2 8 II 3PWP4 5 III-2 Total 100

(19) It can be seen from the comparison between Comparative Example 2 and Example 2 that the liquid crystal composition comprising the compound of general formula I and the compound of general formula of the present invention has a larger vertical dielectric constant (?.sub.?), a larger ratio of the vertical dielectric constant to the absolute value of dielectric anisotropy (?.sub.?/|??|), a larger K.sub.ave value and a higher transmittance in view of the liquid crystal composition comprising only the compound of general formula II of the present invention, while maintaining an appropriate clearing point, an appropriate optical anisotropy, and an appropriate absolute value of the dielectric anisotropy.

Example 3

(20) The liquid crystal composition of Example 3 is prepared according to each compound and weight percentage listed in Table 7 and is tested by filling the same between two substrates of a liquid crystal display device.

(21) TABLE-US-00007 TABLE 7 Formulation and test performances of liquid crystal composition Weight Code of Test results for the Code of component percent structure performance parameters 3CWO2 14 N-2 Cp 78 3CCWO2 8 N-5 ?n 0.107 VCPWO2 5 I-1 ?.sub.? 7.3 VCPWO4 5 I-1 ?? ?4.5 3CPO2 6 M-2 K.sub.ave 13.8 3CPP2 8 M-16 T.sub.r 13.9 VCCP1 8 M-12 ?.sub.?/|??| 1.62 3CCV 30 M-1 3CCV1 6 M-1 3OWO2 5 II 3PPWO2 5 III-1 Total 100

Example 4

(22) The liquid crystal composition of Example 4 is prepared according to each compound and weight percentage listed in Table 8 and is tested by filling the same between two substrates of a liquid crystal display device.

(23) TABLE-US-00008 TABLE 8 Formulation and test performances of liquid crystal composition Weight Code of Test results for the Code of component percent structure performance parameters 3CWO2 14 N-2 Cp 79 3CCWO2 8 N-5 ?n 0.109 1VCPWO2 5 I-2 ?.sub.? 7.4 2VCPWO3 5 I-2 ?? ?4.5 3CPO2 6 M-2 K.sub.ave 14.1 3CPP2 8 M-16 T.sub.r 14.2 VCCP1 8 M-12 ?.sub.?/|??| 1.64 3CCV 30 M-1 3CCV1 6 M-1 3OWO2 5 II 3PPWO2 5 III-1 Total 100

Example 5

(24) The liquid crystal composition of Example 5 is prepared according to each compound and weight percentage listed in Table 9 and is tested by filling the same between two substrates of a liquid crystal display device.

(25) TABLE-US-00009 TABLE 9 Formulation and test performances of liquid crystal composition Weight Code of Test results for the Code of component percent structure performance parameters 3CWO2 10 N-2 Cp 79 3CCWO2 7 N-5 ?n 0.106 1VCPWO2 4 I-2 ?.sub.? 7.4 3VCPWO2 4 I-2 ?? ?4.4 3CPO2 8 M-2 K.sub.ave 13.7 5PP1 6 M-6 T.sub.r 14.1 VCCP1 6 M-12 ?.sub.?/|??| 1.68 3CC2 10 M-1 3CCV 25 M-1 3CCV1 6 M-1 3OPWO2 9 II 3PWP2 5 III-2 Total 100

Example 6

(26) The liquid crystal composition of Example 6 is prepared according to each compound and weight percentage listed in Table 10 and is tested by filling the same between two substrates of a liquid crystal display device.

(27) TABLE-US-00010 TABLE 10 Formulation and test performances of liquid crystal composition Weight Code of Test results for the Code of component percent structure performance parameters 3CWO4 15 N-2 Cp 78 3CCWO2 7 N-5 ?n 0.107 4VCPWO3 5 I-2 ?.sub.? 7.5 3VCPWO2 5 I-2 ?? ?4.5 V2CCP1 8 M-12 K.sub.ave 13.8 VCCP1 8 M-12 T.sub.r 14 3CC2 18 M-1 ?.sub.?/|??| 1.67 5CC3 8 M-1 5PP1 8 M-6 3PPWO2 4 III-1 3PPWO4 4 III-1 3OPWO2 5 II 3OPWO4 5 II Total 100

Example 7

(28) The liquid crystal composition of Example 7 is prepared according to each compound and weight percentage listed in Table 11 and is tested by filling the same between two substrates of a liquid crystal display device.

(29) TABLE-US-00011 TABLE 11 Formulation and test performances of liquid crystal composition Weight Code of Test results for the Code of component percent structure performance parameters 3OWO4 12 II Cp 82 3CCWO2 6 N-5 ?n 0.108 3CCWO3 6 N-5 ?.sub.? 7.3 1VCPWO2 8 I-2 ?? ?4.6 V2CCP1 6 M-12 K.sub.ave 14.1 VCCP1 6 M-12 T.sub.r 13.8 3CCV 25 M-1 ?.sub.?/|??| 1.59 3CCV1 8 M-1 5PP1 5 M-6 3PWP2 4 III-2 3PWP4 4 III-2 3OPWO2 5 II 3OPWO4 5 II Total 100

Example 8

(30) The liquid crystal composition of Example 8 is prepared according to each compound and weight percentage listed in Table 12 and is tested by filling the same between two substrates of a liquid crystal display device.

(31) TABLE-US-00012 TABLE 12 Formulation and test performances of liquid crystal composition Weight Code of Test results for the Code of component percent structure performance parameters 3OWO4 6 II Cp 78 3CWO2 12 N-2 ?n 0.107 3CCWO3 6 N-5 ?.sub.? 7.1 1VCPWO3 6 I-2 ?? ?4.5 V2CCP1 5 M-12 K.sub.ave 13.8 VCCP1 5 M-12 T.sub.r 13.9 3CCV 28 M-1 ?.sub.?/|??| 1.58 3CCV1 6 M-1 3CPP2 8 M-16 3PPWO2 4 III-1 3PPWP4 4 N-17 3OPWO2 5 II 3OPWO4 5 II Total 100

Example 9

(32) The liquid crystal composition of Example 9 is prepared according to each compound and weight percentage listed in Table 13 and is tested by filling the same between two substrates of a liquid crystal display device.

(33) TABLE-US-00013 TABLE 13 Formulation and test performances of liquid crystal composition Weight Code of Test results for the Code of component percent structure performance parameters 3CWO4 8 N-2 Cp 79 3CWO2 10 N-2 ?n 0.105 3CCWO3 6 N-5 ?.sub.? 7.3 1VCPWO3 4 I-2 ?? ?4.6 1VCPWO5 4 I-2 K.sub.ave 14 V2CCP1 5 M-12 T.sub.r 13.8 1PP2V 5 M-6 ?.sub.?/|??| 1.59 3CCV 28 M-1 3CCV1 6 M-1 3CPP2V 6 M-16 3PWP2 4 III-2 3PWP4 4 III-2 3OPWO2 5 II 3OPWO4 5 II Total 100

Example 10

(34) The liquid crystal composition of Example 10 is prepared according to each compound and weight percentage listed in Table 14 and is tested by filling the same between two substrates of a liquid crystal display device.

(35) TABLE-US-00014 TABLE 14 Formulation and test performances of liquid crystal composition Weight Code of Test results for the Code of component percent structure performance parameters 3C1OWO2 14 N-3 Cp 80 3CC1OWO2 8 N-6 ?n 0.106 2VCPWO3 5 I-2 ?.sub.? 7.4 3VCPWO2 5 I-2 ?? ?4.7 V2CCP1 6 M-12 K.sub.ave 14.2 VCCP1 8 M-12 T.sub.r 14 3CCV 22 M-1 ?.sub.?/|??| 1.58 3CCV1 8 M-1 5PP1 8 M-6 3PPWO2 3 III-1 3PPWO4 3 III-1 3OPWO2 5 II 3OPWO4 5 II Total 100

Example 11

(36) The liquid crystal composition of Example 11 is prepared according to each compound and weight percentage listed in Table 15 and is tested by filling the same between two substrates of a liquid crystal display device.

(37) TABLE-US-00015 TABLE 15 Formulation and test of liquid crystal composition Weight Code of Test results for the Code of component percent structure performance parameters 3C1OWO2 16 N-3 Cp 81 3CC1OWO2 5 N-6 ?n 107 4CC1OWO2 5 N-6 ?.sub.? 7.5 1VCPWO3 4 I-2 ?? ?4.8 1VCPWO5 4 I-2 K.sub.ave 14.1 V2CCP1 6 M-12 T.sub.r 14.3 1PP2V 8 M-6 ?.sub.?/|??| 1.56 3CC2 18 M-1 5CC3 8 M-1 5PP1 8 M-6 3PWP2 4 III-2 3PWP4 4 III-2 3OPWO2 5 II 3OPWO4 5 II Total 100

(38) In conclusion, the liquid crystal composition of the present invention has a larger vertical dielectric constant (?.sub.?), a larger ratio of the vertical dielectric constant to the absolute value of dielectric anisotropy (?.sub.?/|??|), a larger K.sub.ave value and a higher transmittance while maintaining an appropriate clearing point, an appropriate optical anisotropy, and an appropriate absolute value of the dielectric anisotropy. In particular when the liquid crystal composition contains the compound of general formula I-2, the performance is significantly improved such that the liquid crystal display device comprising the liquid crystal composition of the present invention has a better contrast, a faster response speed and a better transmittance while maintaining an appropriate range of operating temperature and an appropriate threshold voltage.

(39) The above embodiments are merely illustrative of the technical concepts and features of the present invention, and provided for facilitating the understanding and practice of the present invention by those skilled in the art. However, the protection scope of the invention is not limited thereto. Equivalent variations or modifications made without departing from the spirit and essence of the present invention are intended to be contemplated within the protection scope of the present invention.

INDUSTRIAL APPLICABILITY

(40) The liquid crystal composition involved in the present invention can be applied to the field of liquid crystal.