Dye-based polarizer as well as polarizing plate and liquid crystal display device using the polarizer

A polarizer containing:

• in a base thereof,
• at least one of an azo compound represented by the following Formula (1) or a salt thereof (as compound A);
• and
• at least one of an azo compound represented by the following Formula (2-I), (2-II), (3), (4-I), (4-II), (5-I) or (5-II), or a salt thereof (as compound B):
• the compound A:
• wherein Ar1 represents a phenyl group or a naphthyl group having at least one substituent of a sulfo group or a carboxy group;
• and
• Rr1 to Rr4 each independently represent a hydrogen atom, a lower alkyl group, a lower alkoxy group or a lower alkoxy group having a sulfo group,
• the compound B:
• wherein Ab1 represents a phenyl group or a naphthyl group having at least one substituent of a sulfo group or a carboxy group;
• Rb1 to Rb5 each independently represent a hydrogen atom, a lower alkyl group, a lower alkoxy group or a lower alkoxy group having a sulfo group;
• and
• Xb1 represents an amino group, a phenylamino group, a phenylazo group, a naphthotriazole group or a benzoylamino group optionally having at least one substituent selected from the group consisting of a lower alkyl group, a lower alkoxy group, a sulfo group, an amino group, a lower alkylamino group, a hydroxyl group, a carboxy group and a carboxyethyl amino group,
• wherein Ab2 represents a phenyl group or a naphthyl group having at least one substituent of a sulfo group or a carboxy group;
• and
• Xb2 represents a phenylamino group, a phenylazo group, a naphthotriazole group or a benzoylamino group optionally having at least one substituent selected from the group consisting of a lower alkyl, a lower alkoxy group, a hydroxyl group, a carboxy group, a sulfo group, an amino group and a substituted amino group,
• wherein Ab3 represents a phenyl group or a naphthyl group having at least one substituent of a sulfo group or a carboxy group;
• Rb6 to Rb8 each independently represent a hydrogen atom, a lower alkyl group, a lower alkoxy group or a lower alkoxyl group having a sulfo group;
• and
• Xb3 represents an amino group, a phenylamino group, a phenylazo group, a benzoyl group, a benzoylamino group or a naphthotriazole group optionally having at least one substituent selected from the group consisting of a lower alkyl, a lower alkoxy group, a hydroxyl group, a carboxy group, a sulfo group, an amino group, a substituted amino group and an aminonaphthyl group, and
• wherein Ag1 represents a nitro group or an amino group,
• Xg1 represents:
• an amino group optionally having at least one substituent selected from the group consisting of a lower alkyl group, a lower alkoxy group and a sulfo group;
• a benzoyl group or a benzoylamino group optionally having at least one substituent selected from the group consisting of a lower alkyl group, a lower alkoxy group, a sulfo group, an amino group and a substituted amino group;
• a phenylamino group optionally having at least one substituent selected from the group consisting of a lower alkyl group, a lower alkoxy group, a sulfo group, an amino group and a substituted amino group;
• a phenylazo group optionally having at least one substituent selected from the group consisting of a lower alkyl group, a lower alkoxy group, a sulfo group, a hydroxyl group, an amino group and a substituted amino group;
• or
• a naphthotriazole group optionally having at least one substituent selected from the group consisting of a lower alkyl group, a lower alkoxy group, a sulfo group, an amino group and a substituted amino group,
• Rg1 and Rg2 of Formula (5-I) each independently represent a hydrogen atom, a hydroxyl group, a lower alkyl group, a lower alkoxy group or a lower alkoxy group having a sulfo group, and
• Rg2 of Formula (5-II) represents a hydrogen atom, a hydroxyl group, a lower alkyl group, a lower alkoxy group or a lower alkoxy group having a sulfo group.