Liquid crystal composition and liquid crystal display device

1. The liquid crystal composition having a nematic phase comprising two components, wherein the first component is at least one compound selected from the group of compounds represented by formulas (1-1-1) to (1-1-4) and (1-2-1); and the second component is at least one compound selected from the group of compounds represented by formula (2):

wherein R 1 is alkyl having 1 to 12 carbons, alkoxy having 1 to 12 carbons or alkenyl having 2 to 12 carbons; X 1 , X 2 , X 3 , X 4 , X 5 , X 6 , X 7 , and X 8 are each independently hydrogen or fluorine;

Y 1 is fluorine, chlorine or trifluoromethoxy; R 2 and R 3 are each independently alkyl having 1 to 12 carbons, alkoxy having 1 to 12 carbons, alkenyl having 2 to 12 carbons, or alkenyl having 2 to 12 carbons in which arbitrary hydrogen is replaced by fluorine; ring D, ring E and ring F are each independently 1,4-cyclohexylene, 1,4-phenylene, 2-fluoro-1,4-phenylene, 3-fluoro-1,4-phenylene, or 2,5-difluoro-1,4-phenylene; Z 1 and Z 2 are each independently a single bond, ethylene or carbonyloxy; and m is 0 or 1.

2. The liquid crystal composition according to claim 1 , wherein the first component is at least one compound selected from the group of compounds represented by formulas (1-1-1), (1-1-2) and (1-2-1).

3. The liquid crystal composition according to claim 1 , wherein the second component is at least one compound selected from the group of compounds represented by formulas (2-1) to (2-6):

wherein R 2 and R 3 are each independently alkyl having 1 to 12 carbons, alkoxy having 1 to 12 carbons, alkenyl having 2 to 12 carbons, or alkenyl having 2 to 12 carbons in which arbitrary hydrogen is replaced by fluorine.

4. The liquid crystal composition according to claim 3 , wherein the second component is at least one compound selected from the group of compounds represented by formula (2-1).

5. The liquid crystal composition according to claim 3 , wherein the second component is a mixture of at least one compound selected from the group of compounds represented by formula (2-1) and at least one compound selected from the group of compounds represented by formula (2-4).

6. The liquid crystal composition according to claim 3 , wherein the second component is a mixture of at least one compound selected from the group of compounds represented by formula (2-1), at least one compound selected from the group of compounds represented by formula (2-4), and at least one compound selected from the group of compounds represented by formula (2-6).

7. The liquid crystal composition according to claim 1 , wherein the ratio of the first component is in the range of approximately 5% to approximately 25% by weight, and the ratio of the second component is in the range of approximately 40% to approximately 85% by weight, based on the total weight of the liquid crystal composition.

8. The liquid crystal composition according to claim 1 , wherein the composition further includes at least one compound selected from the group of compounds represented by formula (3) as the third component:

wherein R 1 is alkyl having 1 to 12 carbons, alkoxy having 1 to 12 carbons or alkenyl having 2 to 12 carbons; ring G is independently 1,4-cyclohexylene, 1,3-dioxane-2,5-diyl, 1,4-phenylene, 2-fluoro-1,4-phenylene, 3-fluoro-1,4-phenylene, 3,5-difluoro-1,4-phenylene, or 2,5-pyrimidine; Z 4 is independently a single bond, ethylene, carbonyloxy, or difluoromethyleneoxy; X 1 and X 2 are each independently hydrogen or fluorine; Y 1 is fluorine, chlorine, or trifluoromethoxy; and n is 1, 2 or 3.

9. The liquid crystal composition according to claim 8 , wherein the third component is at least one compound selected from the group of compounds represented by formulas (3-1) to (3-17):

wherein R 4 is alkyl having 1 to 12 carbons or alkenyl having 2 to 12 carbons.

10. The liquid crystal composition according to claim 9 , wherein the third component is at least one compound selected from the group of compounds represented by formula (3-9).

11. The liquid crystal composition according to claim 9 , wherein the third component is at least one compound selected from the group of compounds represented by formula (3-11).

12. The liquid crystal composition according to claim 9 , wherein the third component is at least one compound selected from the group of compounds represented by formula (3-17).

13. The liquid crystal composition according to claim 9 , wherein the third component is a mixture of at least one compound selected from the group of compounds represented by formula (3-6) and at least one compound selected from the group of compounds represented by formula (3-11).

14. The liquid crystal composition according to claim 9 , wherein the third component is a mixture of at least one compound selected from the group of compounds represented by formula (3-9) and at least one compound selected from the group of compounds represented by formula (3-11).

15. The liquid crystal composition according to claim 9 , wherein the third component is a mixture of at least one compound selected from the group of compounds represented by formula (3-11) and at least one compound selected from the group of compounds represented by formula (3-17).

16. The liquid crystal composition according to claim 8 , wherein the ratio of the third component is in the range of approximately 5% to approximately 60% by weight based on the total weight of the liquid crystal composition.

17. The liquid crystal composition according to claim 1 , wherein the composition has a maximum temperature of a nematic phase of approximately 70° C. or more, an optical anisotropy (25° C.) at a wavelength of 589 nm of approximately 0.08 or more, and a dielectric anisotropy (25° C.) at a frequency of 1 kHz of approximately 2 or more.

18. A liquid crystal display device that includes the liquid crystal composition according to claim 1 .

19. The liquid crystal display device according to claim 18 , wherein the operation mode of the liquid crystal display device is a TN mode, an OCB mode, an IPS mode, or a PSA mode, and the driving mode of the liquid crystal display device is an active matrix mode.