Nematic liquid crystal composition and liquid crystal display device using same
A liquid crystal composition having negative dielectric anisotropy, large refractive index anisotropy, and low viscosity and containing as a first component, one or two or more compounds represented by general formula (I) and, as a second component, one or two or more compounds represented by general formula (II), wherein dielectric anisotropy (Δε) at 25° C. is −2.0 or less. Also, a liquid crystal display device having high contrast, fast response, and excellent display quality without causing image sticking and display defects.
1. A nematic liquid crystal composition comprising, as a first component, at least one compound represented by general formula (I)
in the formula, R 1 represents a linear alkyl group or branched alkyl group having 1 to 24 carbon atoms, one or two or more CH 2 groups in the alkyl group may be substituted by —O—, —CO—, —OCO—, or —COO— so that oxygen atoms are not directly adjacent to each other, and M 1 represents a single bond, and, as s second component, at least one compound represented by general formula (II)
in the formula, R 21 and R 22 each independently represent an alkyl group or alkoxy group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, n 21 represents 0 or 1, X 21 to X 24 each independently represent a hydrogen atom or a fluorine atom, and at least one of X 21 to X 24 represents a fluorine atom, wherein dielectric anisotropy (Δε) at 25° C. is −2.0 or less.
2. The nematic liquid crystal composition according to claim 1 , comprising, as a third component, one or two or more compounds represented by general formula (III),
in the formula, R 31 and R 32 each independently represent an alkyl group or alkoxy group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, M 31 represents a trans-1,4-cyclohexylene group, one or two —CH 2 — in the trans-1,4-cyclohexylene group may be substituted by —O— so that oxygen atoms are not directly adjacent to each other, one or two hydrogen atoms in the phenylene group may be substituted by a fluorine atom, L 31 represents a single bond, —CH 2 CH 2 —, or —CH 2 O—, and n 31 represents 0 or 1.
3. The liquid crystal composition according to claim 1 , comprising a compound selected from a compound group represented by general formula (IV-a) to general formula (IV-d),
in the formulae, R 41 to R 48 each independently represent an alkyl group or alkoxy group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms.
4. The nematic liquid crystal composition according to claim 1 , wherein in the general formula (I), R 1 represents a linear alkyl group or branched alkyl group having 1 to 10 carbon atoms.
5. The nematic liquid crystal composition according to claim 1 , wherein the content of the compound represented by the general formula (I) is 0.001% by mass to 1% by mass, and the content of the compound represented by the general formula (II) is 5% by mass to 30% by mass.
6. The nematic liquid crystal composition according to claim 1 , comprising a polymerizable compound represented by general formula (V),
in the formula, X 51 and X 52 each independently represent a hydrogen atom or a methyl group,
Sp 1 and Sp 2 each independently represent a single bond, an alkylene group having 1 to 8 carbon atoms, or —O—(CH 2 ) s — wherein s represents an integer of 2 to 7, and an oxygen atom is bonded to an aromatic ring,
Z 51 represents —OCH 2 —, —CH 2 O—, —COO—, —OCO—, —CF 2 O—, —OCF 2 —, —CH 2 CH 2 —, —CF 2 CF 2 —, —CH═CH—COO—, —CH═CH—OCO—, —COO—CH═CH—, —OCO—CH═CH—, —COO—CH 2 CH 2 —, —OCO—CH 2 CH 2 —, —CH 2 CH 2 —COO—, —CH 2 CH 2 —OCO—, —COO—CH 2 —, —OCO—CH 2 —, —CH 2 —COO—, —CH 2 —OCO—, —CY 1 ═CY 2 — wherein Y 1 and Y 2 each independently represent a fluorine atom or a hydrogen atom, —C≡C—, or a single bond,
M 51 represents a 1,4-phenylene group, a trans-1,4-cyclohexylene group, or a single bond, and any hydrogen atom of all 1,4-phenylene groups in the formula may be substituted by a fluorine atom.
7. A liquid crystal display device comprising a first substrate provided with a common electrode composed of a transparent conductive material, a second substrate provided with a pixel electrode that is composed of a transparent conductive material and a thin film transistor that controls the pixel electrode provided for each pixel, and a liquid crystal composition held between the first substrate and the second substrate, wherein alignment of liquid crystal molecules in the liquid crystal composition with no voltage applied is substantially vertical to the substrates, and the nematic liquid crystal composition according to claim 1 is used as the liquid crystal composition.
8. A polymer stabilized-mode liquid crystal display device produced by polymerizing a polymerizable compound contained in a liquid crystal composition with or without a voltage applied, wherein the nematic liquid crystal composition containing the polymerizable compound according to claim 6 is used as the liquid crystal composition.