Liquid crystal display device and liquid crystal composition
View Patent ↗The subject is to show a liquid crystal display device having characteristics such as a short response time, a large voltage holding ratio, a low threshold voltage, a large contrast ratio, a long service life and a small flicker rate. The means concerns a liquid crystal display device including a first substrate, a second substrate and a liquid crystal composition having positive dielectric anisotropy, which is placed between these substrates, wherein the liquid crystal composition has a nematic phase and includes at least one compound selected from the group of compounds represented by formula (1) as a first component: in formula (1), R 1 is alkyl or the like; ring A is 1,4-phenylene or the like; Z 1 is a single bond or the like; X 1 and X 2 is hydrogen or fluorine; Y 1 is fluorine or the like; and m is 0, 1, 2, 3 or 4.
1. A liquid crystal display device comprising a first substrate, a second substrate and a liquid crystal composition having a nematic phase and having positive dielectric anisotropy, which is placed between these substrates and comprises at least one compound selected from compounds represented by formula (1) as a first component, and at least one compound selected from compounds represented by formula (2) as a second component, wherein a flicker rate is in the range of 0% to 1%,
in formula (1), R 1 is alkyl having 1 to 12 carbons, alkoxy having 1 to 12 carbons or alkenyl having 2 to 12 carbons; ring A is 1,4-cyclohexylene, 1,4-phenylene, 2-fluoro-1,4-phenylene, 2,3-difluoro-1,4-phenylene, 2,5-difluoro-1,4-phenylene, 2,6-difluoro-1,4-phenylene, 2,3,5-trifluoro-1,4-phenylene, pyrimidine-2,5-diyl, 1,3-dioxane-2,5-diyl, tetrahydropyran-2,5-diyl or naphthalene-2,6-diyl; Z 1 is a single bond, ethylene, vinylene, methyleneoxy, carbonyloxy or difluoromethyleneoxy; X 1 and X 2 are independently hydrogen or fluorine; Y 1 is fluorine, chlorine, alkyl having 1 to 12 carbons in which at least one hydrogen has been replaced by halogen, alkoxy having 1 to 12 carbons in which at least one hydrogen has been replaced by halogen or alkenyloxy having 2 to 12 carbons in which at least one hydrogen has been replaced by halogen; m is 0, 1, 2, 3 or 4, and
in formula (2), R 2 and R 3 are independently alkyl having 1 to 12 carbons, alkoxy having 1 to 12 carbons, alkenyl having 2 to 12 carbons, alkyl having 1 to 12 carbons in which at least one hydrogen has been replaced by halogen or alkenyl having 2 to 12 carbons in which at least one hydrogen has been replaced by halogen; ring B and ring C are independently 1,4-cyclohexylene, 1,4-phenylene, 2-fluoro-1,4-phenylene or 2,5-difluoro-1,4-phenylene; Z 2 is a single bond, ethylene or carbonyloxy; n is 1, 2 or 3.
2. The liquid crystal display device according claim 1 , wherein the first component of the liquid crystal composition is at least one compound selected from the group of compounds represented by formula (1-1) to formula (1-21):
in formula (1-1) to formula (1-21), R 1 is alkyl having 1 to 12 carbons, alkoxy having 1 to 12 carbons or alkenyl having 2 to 12 carbons; X 1 to X 14 are independently hydrogen or fluorine; Y 1 is fluorine, chlorine, alkyl having 1 to 12 carbons in which at least one hydrogen has been replaced by halogen or alkoxy having 1 to 12 carbons in which at least one hydrogen has been replaced by halogen.
3. The liquid crystal display device according to claim 1 , wherein the proportion of the first component of the liquid crystal composition is in the range of 15% by weight to 60% by weight based on the weight of the liquid crystal composition.
4. The liquid crystal display device according to claim 1 , wherein the second component of the liquid crystal composition is at least one compound selected from the group of compounds represented by formula (2-1) to formula (2-13):
in formula (2-1) to formula (2-13), R 2 and R 3 are independently alkyl having 1 to 12 carbons, alkoxy having 1 to 12 carbons, alkenyl having 2 to 12 carbons, alkyl having 1 to 12 carbons in which at least one hydrogen has been replaced by halogen or alkenyl having 2 to 12 carbons in which at least one hydrogen has been replaced by halogen.
5. The liquid crystal display device according to claim 1 , wherein the proportion of the second component of the liquid crystal composition is in the range of 40% by weight to 80% by weight based on the weight of the liquid crystal composition.
6. The liquid crystal display device according to claim 1 , wherein the liquid crystal composition comprises at least one compound selected from the group of compounds represented by formula (3) as a third component:
in formula (3), R 4 and R 5 are independently alkyl having 1 to 12 carbons, alkoxy having 1 to 12 carbons, alkenyl having 2 to 12 carbons, alkenyloxy having 2 to 12 carbons or alkyl having 1 to 12 carbons in which at least one hydrogen has been replaced by halogen; ring D and ring F are independently 1,4-cyclohexylene, 1,4-cyclohexenylene, 1,4-phenylene, 1,4-phenylene in which at least one hydrogen has been replaced by fluorine or chlorine, or tetrahydropyran-2,5-diyl; ring E is 2,3-difluoro-1,4-phenylene, 2-chloro-3-fluoro-1,4-phenylene, 2,3-difluoro-5-methyl-1,4-phenylene, 3,4,5-trifluoronaphthalene-2,6-diyl or 7,8-difluorochroman-2,6-diyl; Z 3 and Z 4 are independently a single bond, ethylene, carbonyloxy or methyleneoxy; e is 1, 2 or 3, f is 0 or 1; and the sum of e and f is 3 or less.
7. The liquid crystal display device according to claim 6 , wherein the third component of the liquid crystal composition is at least one compound selected from the group of compounds represented by formula (3-1) to formula (3-19):
in formula (3-1) to formula (3-19), R 4 and R 5 are independently alkyl having 1 to 12 carbons, alkoxy having 1 to 12 carbons, alkenyl having 2 to 1.2 carbons, alkenyloxy having 2 to 12 carbons or alkyl having 1 to 12 carbons in which at least one hydrogen has been replaced by halogen.
8. The liquid crystal display device according to claim 6 , wherein the proportion of the third component of the liquid crystal composition is in the range of 3% by weight to 20% by weight based on the weight of the liquid crystal composition.
9. The liquid crystal display device according to claim 1 , wherein in the liquid crystal composition, the maximum temperature of a nematic phase is 70° C. or higher, the optical anisotropy (measured at 25° C.) at a wavelength of 589 nanometers is 0.07 or more, and the dielectric anisotropy (measured at 25° C.) at a frequency of 1 kHz is 2 or more.
10. The liquid crystal display device according to claim 1 , wherein an operating mode of the liquid crystal display device is a TN mode, an ECB mode, an OCB mode, an IPS mode, an FFS mode or an FPA mode and a driving mode of the liquid crystal display device is an active matrix mode.
11. The liquid crystal display device according to claim 1 , wherein an operating mode of the liquid crystal display device is an IPS mode or FFS mode, and a driving mode of the liquid crystal display device is an active matrix mode.
12. A liquid crystal composition comprised in a liquid crystal display device according to claim 1 .