Liquid crystal display device and useful liquid crystal composition
Provided is a liquid crystal display device of the VAIPS mode which uses a liquid crystal material having positive dielectric anisotropy and which has a fast response speed and excellent viewing angle characteristics without having a special cell structure such as pixel partitioning. Disclosed is a liquid crystal display device including: a plurality of independently controllable pixels; and a liquid crystal composition layer having positive dielectric anisotropy, wherein electrodes for controlling the pixels are provided on at least one of first and second substrates that interpose the liquid crystal phase, the long axis of the liquid crystal molecules of the liquid crystal composition layer is aligned substantially perpendicularly to the substrate surface or is in a hybrid alignment, the liquid crystal composition contains one kind or two or more kinds of compounds selected from a specific liquid crystal compound group, and the transmittance of the light that penetrates through the liquid crystal composition layer is modulated at the electric field generated by the electrode structure.
1. A liquid crystal display device comprising:
a first substrate;
a second substrate; and
a liquid crystal composition layer having positive dielectric anisotropy that is interposed between the first substrate and the second substrate, the liquid crystal display device having a plurality of pixels, with each of the pixels being independently controllable and comprising a pair of a pixel electrode and a common electrode, wherein the pair of a pixel electrode and the common electrode are provided on the first substrate, or the second substrate or both the first substrate and the second substrate, the long axis of liquid crystal molecules of the liquid crystal composition layer is aligned substantially perpendicularly to the substrate surface or is in a hybrid alignment,
wherein a liquid crystal composition of the liquid crystal composition layer comprises one or more compounds selected from the group consisting of compounds represented by General Formula (LC1) to General Formula (LC5):
wherein R 1 represents an alkyl group having 1 to 15 carbon atoms; one or more CH 2 groups in the alkyl group may be substituted by —O—, —CH═CH—, —CO—, —OCO—, —COO—, —C≡C—, —CF 2 O— or —OCF 2 — such that O atoms are not directly adjacent to each other; one or two or more H atoms in the alkyl group may be optionally substituted by halogen; A 1 , A 2 and A 3 each independently represent any one of the following structures:
wherein X 1 and X 2 each independently represent H, Cl, F, CF 3 or OCF 3 ; one or more CH 2 groups in A 1 and A 2 may be substituted by —CH═CH—, —CF 2 O— or —OCF 2 —; one or more CH groups in A 1 and A 2 may be substituted by N atoms; one or more H atoms in A 1 and A 2 may be substituted by Cl, F, CF 3 or OCF 3 ; X 1 to X 5 each independently represent H, Cl, F, CF 3 or OCF 3 ; Y represents Cl, F, CF 3 or OCF 3 ; Z 1 to Z 4 each independently represent a single bond, —CH═CH—, —C≡C—, —CH 2 CH 2 —, —(CH 2 ) 4 —, —OCH 2 —, —CH 2 O—, —OCF 2 — or —CF 2 O—; at least one of Z 1 and Z 2 that exist is not a single bond; Z 5 represents a CH 2 group or an O atom; m 1 and m 2 each independently represent an integer from 0 to 3; m 1 +m 2 represents 1, 2 or 3; and m 3 each independently represent an integer from 0 to 2; and
the transmittance of light that has penetrated through the liquid crystal composition layer is modulated at the electric field generated by the electrode structure described above
wherein the liquid crystal composition does not include a compound having a cyano group.
2. The liquid crystal display device according to claim 1 , wherein the liquid crystal composition further comprises one or more compounds represented by General Formula (LC6):
wherein R 1 and R 2 each independently represent an alkyl group having 1 to 15 carbon atoms; one or more CH 2 groups in the alkyl group may be substituted by —O—, —CH═CH—, —CO—, —COO—, —C≡C—, —CF 2 O— or —OCF 2 — such that O atoms are not directly adjacent to each other; one or more H atoms in the alkyl group may be optionally substituted by halogen; Z 3 and Z 4 each independently represent a single bond, —CH═CH—, —C≡C—, —CH 2 CH 2 —, —(CH 2 ) 4 —, —OCH 2 —, —CH 2 O—, —OCF 2 — or —CF 2 O— such that O atoms are not directly adjacent to each other; one or more H atoms in the alkyl group may be optionally substituted by halogen; Z 3 and Z 4 each independently represent a single bond; ml represents an integer from 0 to 3; B 1 to B 3 each independently represent any one of the following structures:
one or more CH 2 groups in B 1 to B 3 may be substituted by —CH═CH—, —CF 2 O— or —OCF 2 —; and one or more CH groups in B 1 to B 3 may be substituted by N atoms.
3. The liquid crystal display device according to claim 1 or 2 , wherein the compound of General Formula (LC1) is one or more compounds selected from the group consisting of compounds represented by General Formula (LC1)-1 to General Formula (LC1)-4:
wherein R 1 represents an alkyl group having 1 to 15 carbon atoms; one or more CH 2 groups in the alkyl group may be substituted by —O—, —CH═CH—, —CO—, —OCO—, —COO—, —C≡C—, —CF 2 O— or —OCF 2 — such that O atoms are not directly adjacent to each other; Y represents Cl, F, CF 3 or OCF 3 ; and X 1 , X 2 , L 1 and L 2 each represent H, Cl, F, CF 3 or OCF 3 .
4. The liquid crystal display device according to claim 1 or 2 , wherein the compound of General Formula (LC2) is one or more compounds selected from the group consisting of compounds represented by General Formula (LC2)-1 to General Formula (LC2)-10:
wherein R 1 represents an alkyl group having 1 to 15 carbon atoms; one or more CH 2 groups in the alkyl group may be substituted by —O—, —CH═CH—, —CO—, —OCO—, —COO—, —C≡C—, —CF 2 O— or —OCF 2 — such that O atoms are not directly adjacent to each other; X 1 , X 2 , L 1 , L 2 , L 3 and L 4 each represent H, Cl, F, CF 3 or OCF 3 .
5. The liquid crystal display device according to claim 1 or 2 , wherein the compound of General Formula (LC3) is one or more compounds selected from the group consisting of compounds represented by the following General Formula (LC3)-1 to General Formula (LC3)-28:
wherein R 1 represents an alkyl group having 1 to 15 carbon atoms; one or more CH 2 groups in the alkyl group may be substituted by —O—, —CH═CH—, —CO—, —OCO—, —COO—, —C≡C—, —CF 2 O— or —OCF 2 — such that O atoms are not directly adjacent to each other; one or more H atoms in the alkyl group may be optionally substituted by halogen; X 2 and X 4 each independently represent H, Cl, F, CF 3 or OCF 3 ; Z 1 represents a single bond, —CH═CH—, —C≡C—, —CH 2 CH 2 —, —(CH 2 ) 4 —, —OCH 2 —, —CH 2 O—, —OCF 2 — or —CF 2 O—; and m 1 represents an integer from 0 to 3.
6. The liquid crystal display device according to claim 1 or 2 , wherein the compound of General Formula (LC4) is one or more compounds selected from the group consisting of compounds represented by the following General Formula (LC4)-1 to General Formula (LC4)-8, and the compound of General Formula (LC5) is one or more compounds selected from the group consisting of compounds represented by the following General Formula (LC5)-1 to General Formula (LC5)-6:
wherein R 1 , X 1 , X 2 , X 4 , X 5 and Y have the same meanings as R 1 , X 1 , X 2 , X 4 , X 5 and Y in General Formula (LC4) or General Formula (LC5), respectively.
7. The liquid crystal display device according to claim 2 , wherein the compound of General Formula (LC6) is one or more compounds selected from the group consisting of compounds represented by the following General Formula (LC6)-1 to General Formula (LC6)-15:
wherein R 1 and R 2 have the same meanings as R 1 and R 2 in General Formula (LC6).
8. The liquid crystal display device according to claim 1 , wherein the liquid crystal composition comprises one or more polymerizable compounds.
9. A liquid crystal display device, wherein the polymerizable compound according to claim 8 is a disc-shaped liquid crystal compound having a structure in which a benzene derivative, a triphenylene derivative, a truxene derivative, a phthalocyanine derivative or a cyclohexane derivative serves as a parent nucleus at the center of the molecule, and a linear alkyl group, a linear alkoxy group or a substituted benzoyloxy group is radially substituted as a side chain.
10. The liquid crystal display device according to claim 8 , wherein the liquid crystal composition does not substantially comprise an initiator.
11. The liquid crystal display device according to claim 8 , wherein the liquid crystal composition comprises a polymerizable compound in an amount of 0.1% to 2.0% by mass is used.
12. The liquid crystal display device according to claim 1 , wherein the liquid crystal composition further comprises one or more oxidation inhibitors.
13. The liquid crystal display device according to claim 1 wherein the liquid crystal composition further comprises one or more UV absorbers.
14. The liquid crystal display device according to claim 1 , wherein a product (Δn·d) of a refractive index anisotropy (Δn) of the liquid crystal composition and a distance (d) between the first substrate and the second substrate of the liquid crystal display device is 0.33 to 0.40.
15. The liquid crystal display device according to claim 1 , wherein a product (Δn·d) of a refractive index anisotropy (Δn) of the liquid crystal composition and a distance (d) between the first substrate and the second substrate of the display device is 0.34 to 0.44.
16. The liquid crystal display device according to claim 1 , wherein an alignment film formed from a polyimide (PI), a chalcone, or a cinnamate is provided on each of the surfaces that are in contact with the liquid crystal composition on the first substrate and the second substrate of the display device.
17. The liquid crystal display device according to claim 1 , wherein an alignment film produced by utilizing a photoalignment technology is provided on each of the surfaces that are in contact with the liquid crystal composition on the first substrate and the second substrate of the liquid crystal display device.
18. The liquid crystal display device according to claim 1 , wherein tilt angle between the substrate and the liquid crystal composition is 85° to 90°.
19. The liquid crystal display device according to claim 1 , wherein a tilt angle between the first substrate or second substrate and the liquid crystal composition is 85° to 90°, and a tilt angle between the other substrate and the liquid crystal composition is 3° to 20°.
20. The liquid crystal display device according to claim 1 , wherein the liquid crystal composition further comprises one or more compounds selected from compounds represented by General Formulas (LC1)-1, (LC2)-1, (LC3)-4, (LC3)-5, (LC3)-6, and (LC3)-11
wherein R 1 represents an alkyl group having 1 to 15 carbon atoms; one or more CH 2 groups in the alkyl group may be substituted by —O—, —CH═CH—, —CO—, —OCO—, —COO—, —C≡C—, —CF 2 O— or —OCF 2 — such that O atoms are not directly adjacent to each other; one or more H atoms in the alkyl group may be optionally substituted by halogen; Y represents Cl, F, CF 3 or OCF 3 ; X 1 and X 2 , each represent H, Cl, F, CF 3 or OCF 3 .
21. The liquid crystal display device according to claim 1 , wherein the liquid crystal composition further comprises one or more compounds selected from compounds represented by General Formulas (LC1)-2, (LC1)-3, (LC1)-4, (LC2)-4, (LC2)-5, (LC2)-6, (LC2)-7, (LC2)-8, (LC2)-9, and (LC2)-10
wherein R 1 represents an alkyl group having 1 to 15 carbon atoms; one or more CH 2 groups in the alkyl group may be substituted by —O—, —CH═CH—, —CO—, —OCO—, —COO—, —C≡C—, —CF 2 O— or —OCF 2 — such that O atoms are not directly adjacent to each other; one or more H atoms in the alkyl group may be optionally substituted by halogen; Y represents Cl, F, CF 3 or OCF 3 ; X 1 , X 2 , L 1 , L 2 , L 3 and L 4 each represent H, Cl, F, CF 3 or OCF 3 .
22. The liquid crystal display device according to claim 1 , wherein the liquid crystal composition further comprises one or more compounds selected from compounds represented by General Formulas (LC3)-3, (LC3)-22, (LC3)-23, (LC3)-24, and (LC3)-25
23. The liquid crystal display device according to claim 1 , wherein the liquid crystal composition further comprises one or more compounds selected from compounds represented by General Formulas (LC6)-1, (LC6)-5, and (LC6)-14
24. The liquid crystal display device according to claim 1 , wherein the liquid crystal composition further comprises one or more compounds selected from compounds represented by General Formulas (LC6)-4, (LC6)-12, and (LC6)-15