Liquid crystal composition and liquid crystal display device
View Patent ↗The invention is to provide a liquid crystal composition that satisfies at least one characteristic among the characteristics such as a high maximum temperature of a nematic phase, a low minimum temperature of a nematic phase, a small viscosity, a large optical anisotropy, a large dielectric anisotropy, a large specific resistance, a high stability to ultraviolet light and a high stability to heat, or that is suitably balanced concerning at least two characteristics. The invention is to provide an AM device that has a short response time, a large voltage holding ratio, a large contrast ratio, a long service life and so forth. The invention is to provide a liquid crystal composition having a nematic phase that contains a specific five-membered ring compound having a large optical anisotropy and a large dielectric anisotropy as a first component and a specific compound having a small viscosity as a second component, and a liquid crystal display device containing the composition.
1. A liquid crystal composition having a nematic phase that comprises at least one compound selected from the group of compounds represented by formulas (1) as a first component and at least one compound selected from the group of compounds represented by formula (2) as a second component:
wherein R 1 is alkyl having 1 to 12 carbons, alkoxy having 1 to 12 carbons or alkenyl having 2 to 12 carbons; 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 A, ring B and ring C 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 , Z 2 and Z 3 are each independently a single bond, ethylene, carbonyloxy or difluoromethyleneoxy, wherein at least one of Z 1 , Z 2 and Z 3 is difluoromethyleneoxy; Z 4 and Z 5 are each independently a single bond, ethylene or carbonyloxy; 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; 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) to (1-3):
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; and Y 1 is fluorine, chlorine or trifluoromethoxy.
3. The liquid crystal composition according to claim 2 , wherein the first component is at least one compound selected from the group of compounds represented by formula (1-1).
4. 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.
5. The liquid crystal composition according to claim 4 , wherein the second component is at least one compound selected from the group of compounds represented by formula (2-1).
6. The liquid crystal composition according to claim 4 , wherein the second component is at least one compound selected from the group of compounds represented by formula (2-6).
7. The liquid crystal composition according to claim 4 , 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).
8. The liquid crystal composition according to claim 4 , 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 (2-6).
9. The liquid crystal composition according to claim 1 , wherein the ratio of the first component is in the range of 5% to 30% by weight, and the ratio of the second component is in the range of 35% to 80% by weight, based on the total weight of the liquid crystal composition.
10. The liquid crystal composition according to claim 1 that further comprises at least one compound selected from the group of compounds represented by formula (3) as a 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 D is independently 1,4-cyclohexylene, 1,3-dioxane-2,5-diyl, 1,4-phenylene, 3-fluoro-1,4-phenylene, 3,5-difluoro-1,4-phenylene or 2,5-pyrimidine; Z 1 is 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.
11. The liquid crystal composition according to claim 10 , 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.
12. The liquid crystal composition according to claim 11 , wherein the third component is at least one compound selected from the group of compounds represented by formula (3-9).
13. The liquid crystal composition according to claim 11 , wherein the third component is at least one compound selected from the group of compounds represented by formula (3-11).
14. The liquid crystal composition according to claim 11 , wherein the third component is at least one compound selected from the group of compounds represented by formula (3-17).
15. The liquid crystal composition according to claim 11 , 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).
16. The liquid crystal composition according to claim 10 , wherein the ratio of the third component is in the range of 5% to 50% by weight based on the total weight of the liquid composition.
17. The liquid crystal composition according to claim 1 , wherein the composition has a maximum temperature of a nematic phase of 70° C. or more, an optical anisotropy (25° C.) of 0.08 or more at a wavelength of 589 nm, and a dielectric anisotropy (25° C.) of 2 or more at a frequency of 1 kHz.
18. A liquid crystal display device that comprises the liquid crystal composition according to claim 1 .
19. A liquid crystal display device according to claim 18 , wherein an operating mode of the liquid crystal display device is a TN mode, an OCB mode or an IPS mode, and a driving mode of the liquid crystal display device is an active matrix mode.
20. A liquid crystal display device according to claim 18 , wherein an operating mode of the liquid crystal display device is a PSA mode and a driving mode of the liquid crystal display device is an active matrix mode.