Patent ID: 7058001

Claim:
A method of generating fluorescence in an information recording medium, comprising the step of: using a chemical species [FL] and a chemical species [Q] in the recording medium; irradiating recording light having a predetermined wavelength λ 1 , said recording light carrying recording information, to the chemical species [FL] and the chemical species [Q] contained in the recording medium, thereby changing a combination of the chemical species [FL] and the chemical species [Q] into a fluorescent material; and irradiating excitation light having a predetermined wavelength λ 2 to the fluorescent material, thereby causing the fluorescent material to emit fluorescence, wherein the chemical species [FL] is a compound represented by Formula (II-1): wherein Z 1 and Z 2 each represent an atom group necessary for forming a five-membered or six-membered, nitrogen-containing heterocyclic ring; R 30 and R 31 each independently represent an alkyl group or an aryl group; L 3 , L 4 , L 5 , L 6 , and L 7 each independently represent a substituted or unsubstituted methine group, provided that, in cases where L 3 to L 7 are substituted by substituents, the substituents may optionally be connected with one another to form a ring; p and q each independently represent 0 or 1; n 1 and n 2 each independently represent 0, 1, or 2; M 1 represents a charge balancing counter ion; and mi represents a number necessary for keeping charge balance; and the chemical species [Q] is a compound represented by Formula (II-2): wherein m and n each independently represent an integer of 0 to 2; X 1 and X 2 each represent ═NR 1 or ═CR 2 R 3 , in which R 1 , R 2 , and R 3 each represent a substituent; and L 1 and L 2 each independently represent a bivalent linking group.