Patent ID: 7632945

Claim:
A cyanine dye represented by General Formula 2: wherein in General Formula 2, X denotes a carbon atom or heteroatom of the group 15 or 16 in the periodic table excluding a nitrogen atom; Z 3 denotes either a benzene or naphthalene ring, while R 1 to R 3 independently denote a hydrogen atom or aliphatic hydrocarbon group, with the proviso that R 1 and/or R 2 are not present when X is a heteroatom; L 1 denotes a divalent group; the symbol “m” is an integer of 2 or larger; Y denotes a monovalent or multivalent anion of organometallic complex selected from the group consisting of azo, thiocatechol chelate, thiobisphenolate chelate, bisdithioi-α-diketone, and bisphenyldithiols; the symbol “n” is the number of charge unit in the anion of said organometallic complex; and the polymethine chain in the cyanine skeleton may bear a substituent and/or cyclic structure, said substituent being a member selected from the group consisting of an aliphatic hydrocarbon group, alicyclic hydrocarbon group, aromatic hydrocarbon group, halogen group, amino group, heterocyclic group, and combinations thereof; and said cyclic structure being a member selected from the group consisting of cyclopentene, cyclopentadiene, cyclohexene, cyclohexadiene, cycloheptene, cyclooctene, cyclooctadiene, and benzene, each of which may have a substitutent similar to those in the polymethine chain.