Liquid crystal composition and liquid crystal display device

1. A liquid crystal composition having a negative dielectric anisotropy comprising two components, wherein the first component is at least one compound selected from the group consisting of compounds represented by formulas (1-1) and (1-2), and the second component is at least one compound selected from the group consisting of compounds represented by formulas (2-1) to (2-3):

wherein R 1 and R 2 are each independently alkyl having 1 to 12 carbons, alkoxy having 1 to 12 carbons or alkenyl having 2 to 12 carbons; R 3 and R 4 are each independently alkyl having 1 to 12 carbons or alkenyl having 2 to 12 carbons, provided that in the alkyl and the alkenyl, arbitrary hydrogen may be replaced by fluorine, and arbitrary —CH 2 — may be replaced by —O—; X 1 and X 2 are each independently fluorine or chlorine; ring A, ring B, ring C and ring D are each independently 1,4-cyclohexylene or 1,4-phenylene; ring E and ring G are each independently 1,4-cyclohexylene, 1,4-phenylene, 2-fluoro-1,4-phenylene or 3-fluoro-1,4-phenylene; ring F is 1,4-cyclohexylene, 1,4-phenylene, 2-fluoro-1,4-phenylene, 3-fluoro-1,4-phenylene or 2,5-difluoro-1,4-phenylene; and Z′ is a single bond or carbonyloxy.

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

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

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

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

6. The liquid crystal composition of claim 1 , wherein a ratio of the first component is from approximately 5% by weight to approximately 50% by weight, and a ratio of the second component is from approximately 35% by weight to approximately 70% by weight, based on the total weight of the liquid crystal composition.

7. The liquid crystal composition of claim 1 , wherein the composition further comprises at least one compound selected from the group consisting of compounds represented by formula (3) as a third component:

wherein R 1 and R 2 are each independently alkyl having 1 to 12 carbons, alkoxy having 1 to 12 carbons or alkenyl having 2 to 12 carbons; ring I is independently 1,4-cyclohexylene or 1,4-phenylene; Z 2 is a single bond, ethylene, carbonyloxy or methyleneoxy; X 3 and X 4 are each independently fluorine or chlorine; and n is 1 or 2.

8. The liquid crystal composition of claim 7 , wherein the third component is at least one compound selected from the group consisting of compounds represented by formulas (3-1) to (3-12):

wherein R 1 and R 2 are each independently alkyl having 1 to 12 carbons, alkoxy having 1 to 12 carbons or alkenyl having 2 to 12 carbons.

9. The liquid crystal composition of claim 7 , wherein the third component is a mixture of at least one compound selected from the group consisting of compounds represented by formula (3-1) and at least one compound selected from the group consisting of compounds represented by formula (3-7).

10. The liquid crystal composition of claim 7 , wherein the third component is a mixture of at least one compound selected from the group consisting of compounds represented by formula (3-1) and at least one compound selected from the group consisting of compounds represented by formula (3-9).

11. The liquid crystal composition of claim 7 , wherein the third component is a mixture of at least one compound selected from the group consisting of compounds represented by formula (3-4) and at least one compound selected from the group consisting of compounds represented by formula (3-9).

12. The liquid crystal composition of claim 7 , wherein a ratio of the first component is from approximately 5% by weight to approximately 50% by weight, a ratio of the second component is from approximately 35% by weight to approximately 70% by weight, and a ratio of the third component is from approximately 5% by weight to approximately 40% by weight, based on the total weight of the liquid crystal composition.

13. The liquid crystal composition of 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 less.

14. A liquid crystal display device that includes the liquid crystal composition of claim 1 .

15. The liquid crystal display device of claim 14 , wherein the liquid crystal display device has an operation mode of a VA mode or an IPS mode, and has a driving mode of an active matrix mode.

16. The liquid crystal display device of claim 14 , wherein the liquid crystal display device has an operation mode of a PSA mode, and has a driving mode of an active matrix mode.