Liquid crystal display device

1. A liquid crystal display device comprising:

a first substrate provided with a reflective electrode configured to reflect ambient light;

a second substrate facing the first substrate;

a liquid crystal layer sandwiched between the first substrate and the second substrate and containing a liquid crystal material that contains a liquid crystal compound containing an alkoxy group and has negative anisotropy of dielectric constant;

an alignment film provided on at least one of the first substrate and the second substrate on a side facing the liquid crystal layer; and

an aromatic polymer that is present between the liquid crystal layer and the alignment film and/or within the alignment film and has a structure derived from a monomer represented by Formula (M1):

P 1 -Sp 1 -R 2 -A 1 -(—Z-A 2 )- n R 3   (M1)

wherein P 1 represents a radically polymerizable group;

Sp 1 represents a linear, branched, or cyclic alkylene group having 1 to 6 carbon atoms, a linear, branched, or cyclic alkyleneoxy group having 1 to 6 carbon atoms, or a direct bond;

R 2 represents an —O— group, an —S— group, an —NH— group, a —CO— group, a —COO— group, an —OCO— group, an —O—COO— group, an —OCH 2 — group, a —CH 2 O— group, an —SCH 2 — group, a —CH 2 S— group, an —N(CH 3 )— group, an —N(C 2 H 5 )— group, an —N(C 3 H 7 )— group, an —N(C 4 H 9 )— group, a —CF 2 O— group, an —OCF 2 — group, a —CF 2 S— group, an —SCF 2 — group, an —N(CF 3 )— group, a —CH 2 CH 2 — group, a —CF 2 CH 2 — group, a —CH 2 CF 2 — group, a —CF 2 CF 2 — group, a —CH═CH— group, a —CF═CF— group, an —C≡C— group, a —CH═CH—COO— group, an —OCO—CH═CH— group, or a direct bond;

Z represents an —O— group, an —S— group, an —NH— group, a —COO— group, a —OCO— group, an —O—COO— group, an —OCH 2 — group, a —CH 2 O— group, an —SCH 2 — group, a —CH 2 S— group, an —N(CH 3 )— group, an —N(C 2 H 5 )— group, an —N(C 3 H 7 )— group, an —N(C 4 H 9 )— group, a —CF 2 O— group, an —OCF 2 — group, a —CF 2 S-group, an —SCF 2 -group, an —N(CF 3 )-group, a —CH 2 CH 2 — group, a —CF 2 CH 2 -group, a —CH 2 CF 2 — group, a —CF 2 CF 2 — group, a —CH═CH— group, a —CF═CF— group, a —C≡C— group, a —CH═CH—COO— group, an —OCO—CH═CH-group, or a direct bond;

R 3 represents an —R 2 -Sp 1 -P 1 group, a hydrogen atom, a halogen atom, a —CN group, an —NO 2 group, an —NCO group, an —NCS group, an —OCN group, an —SCN group, an —SF 5 group, or a linear or branched alkyl group having 1 to 18 carbon atoms;

A 1 and A 2 each independently represent a 1,2-phenylene group, a 1,3-phenylene group, a 1,4-phenylene group, a naphthalene-1,4-diyl group, a naphthalene-1,5-diyl group, a naphthalene-2,6-diylgroup, a decahydronaphthalene-2,6-diyl group, a 1,2,3,4-tetrahydronaphthalene-2,6-diyl group, a phenanthrene-1,6-diyl group, a phenanthrene-1,8-diyl group, a phenanthrene-2,7-diyl group, a phenanthrene-3,6-diyl group, an anthracene-1,5-diyl group, an anthracene-1,8-diyl group, an anthracene-2,6-group, or an anthracene-2,7-diyl group;

n is 0, 1, or 2;

a hydrogen atom included in R 3 is optionally substituted with a fluorine atom or a chlorine atom;

a —CH 2 — group included in R 3 is optionally substituted with an —O-group, an —S— group, an —NH— group, a —CO— group, a —COO— group, an —OCO— group, an —O—COO— group, an —OCH 2 — group, a —CH 2 O— group, an —SCH 2 — group, a —CH 2 S— group, an —N(CH 3 )— group, an —N(C 2 H 5 )— group, an —N(C 3 H 7 )— group, an —N(C 4 H 9 )— group, a —CF 2 O— group, an —OCF 2 — group, a —CF 2 S— group, an —SCF 2 — group, an —N(CF 3 )— group, a —CH 2 CH 2 — group, a —CF 2 CH 2 — group, a —CH 2 CF 2 — group, a —CF 2 CF 2 — group, a —CH═CH-group, a —CF═CF— group, a —C≡C— group, a —CH═CH—COO— group, or an —OCO—CH═CH— group, with the proviso that an oxygen atom and a sulfur atom are not adjacent to each other,

a —CH 2 — group included in A 1 and A 2 is optionally substituted with an —O— group or an —S— group, with the proviso that an oxygen atom and a sulfur atom are not adjacent to each other; and

one or more hydrogen atoms included in A 1 and A 2 are each optionally substituted with a fluorine atom, a chlorine atom, a —CN group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkylcarbonyl group having 2 to 6 carbon atoms, an alkoxycarbonyl group having 2 to 6 carbon atoms, or an alkylcarbonyloxy group having 2 to 6 carbon atoms.

2. The liquid crystal display device according to claim 1 ,

wherein the monomer represented by Formula (M1) is at least one selected from monomers represented by Formulae (M1-1) to (M1-3):

3. The liquid crystal display device according to claim 1 ,

wherein the liquid crystal compound comprises a group represented by Formula (L):

wherein Xs each independently represent a halogen atom or a hydrogen atom; and R1 represents a hydrocarbon group having 1 to 8 carbon atoms in which a hydrogen atom is optionally substituted with a fluorine atom.

4. The liquid crystal display device according to claim 1 ,

wherein the liquid crystal material has an anisotropy of dielectric constant of −5.0 or less.

5. The liquid crystal display device according to claim 1 ,

wherein the reflective electrode comprises at least one metal selected from the group consisting of Al, Ag, Cu, Zn, and alloys thereof.

6. The liquid crystal display device according to claim 1 ,

wherein the aromatic polymer further comprises a structure derived from a monomer represented by Formula (M2):

wherein A 3 and A 4 each independently represent a phenyl group, a phenylene group, a biphenyl group, a biphenylene group, a linear or branched alkyl group having 1 to 12 carbon atoms, a linear or a branched alkylene group having 1 to 12 carbon atoms, a linear or branched alkenyl group having 2 to 12 carbon atoms, or a linear or branched alkenylene group having 2 to 12 carbon atoms, and at least one selected from A 3 and A 4 contains an -Sp 2 -P 2 group;

P 2 represents a polymerizable group;

Sp 2 represents a linear, branched, or cyclic alkylene group having 1 to 6 carbon atoms, a linear, branched, or cyclic alkyleneoxy group having 1 to 6 carbon atoms, or a direct bond;

m is 1 or 2;

a dotted line connecting A 3 and Y and a dotted line connecting A 4 and Y together indicate that a bond via Y is optionally present between A 3 and A 4 ;

Y represents a —CH 2 — group, a —CH 2 CH 2 — group, a —CH═CH-group, an —O— group, an —S— group, an —NH— group, an —N(CH3)— group, an —N(C 2 H 5 )— group, an —N(C 3 H 7 )— group, an —N(C 4 H 9 )— group, an —OCH 2 — group, a —CH 2 O— group, an —SCH 2 — group, a —CH 2 S— group, or a direct bond;

a hydrogen atom included in A 3 and A 4 is optionally substituted with an -Sp 2 -P 2 group, a halogen atom, a —CN group, an —NO 2 group, an —NCO group, an —NCS group, an —OCN group, an —SCN group, an —SF 5 group, a linear or branched alkyl group having 1 to 12 carbon atoms, a linear or branched alkenyl group having 2 to 12 carbon atoms, or a linear or branched aralkyl group having 7 to 12 carbon atoms;

two adjacent hydrogen atoms included in A 3 and A 4 are optionally substituted with a linear or branched alkylene group having 1 to 12 carbon atoms or a linear or branched alkenylene group having 2 to 12 carbon atoms to form a cyclic structure;

a hydrogen atom of the alkyl group, the alkenyl group, the alkylene group, the alkenylene group, or the aralkyl group included in A 3 and A 4 is optionally substituted with an -Sp 2 -P 2 group; and

a —CH 2 — group in the alkyl group, the alkenyl group, the alkylene group, the alkenylene group, or the aralkyl group included in A 3 and A 4 is optionally substituted with an —O— group, an —S— group, an —NH— group, a —CO— group, a —COO— group, an —OCO— group, an —O—COO— group, an —OCH 2 — group, a —CH 2 O— group, an —SCH 2 — group, a —CH 2 S— group, an —N(CH 3 )— group, an —N(C 2 H 5 )— group, an —N(C 3 H 7 )-group, an —N(C 4 H 9 )— group, a —CF 2 O-group, an —OCF 2 — group, a —CF 2 S— group, an —SCF 2 — group, an —N(CF 3 )— group, a —CH 2 CH 2 — group, a —CF 2 CH 2 — group, a —CH 2 CF 2 — group, a —CF 2 CF 2 — group, a —CH═CH— group, a —CF═CF— group, a —C≡C— group, a —CH═CH—COO— group, or an —OCO—CH═CH— group, with the proviso that an oxygen atom, a sulfur atom, and a nitrogen atom are not adjacent to each other.

7. The liquid crystal display device according to claim 6 ,

wherein the monomer represented by Formula (M2) is a monomer represented by Formula (M2-1):

8. The liquid crystal display device according to claim 1 ,

wherein the alignment film comprises at least one polymer selected from a polyamic acid and a polyimide, and the at least one polymer contains an aliphatic acid anhydride monomer unit.

9. The liquid crystal display device according to claim 8 ,

wherein the polyamic acid has a structure represented by Formula (P-1), and

the polyimide has a structure represented by Formula (P-2):

wherein in each of Formulae (P-1) and (P-2), X 1 has at least one structure selected from the group consisting of structures represented by Formulae (X-1) to (X-6); Y 1 represents a trivalent aromatic or aliphatic group; Z 1 represents a monovalent organic group or a hydrogen atom; and p represents an integer of 1 or greater,

10. The liquid crystal display device according to claim 1 ,

wherein the alignment film is a vertical alignment film.