Patent ID: 7255936

Claim:
A polymeric fluorescent substance exhibiting fluorescence in the solid state and having a polystyrene reduced number average molecular weight of 10 3 to 10 8 , which is a random copolymer and comprises one or more repeating units represented by formula (1) and one or more repeating units represented by formula (3), —Ar 1 — (1) wherein Ar 1 represents an arylene group or a divalent heterocyclic compound group and has 1 to 4 substituents, and wherein the substituents are represented by the following formula (2), wherein X 1 represents a divalent hydrocarbon group; Ar 2 represents an arylene group or a divalent heterocyclic compound group; Ar 3 represents an aryl group or a monovalent heterocyclic compound group; Ar 2 and Ar 3 may be mutually connected to form a ring; Ar 4 represents an aryl group or a monovalent heterocyclic compound group; Ar 3 and Ar 4 may be mutually connected to form a ring; k is 0 or 1; 1 represents an integer of 1 to 3, —Ar 5 — (3) wherein Ar 5 represents an arylene group or divalent heterocyclic compound group represented by formula (4) or (5): wherein X 2 represents a group selected from O, S, SO, SO 2 , N—R 3 , CR 4 R 5 , SiR 6 R 7 ; R 3 to R 7 each independently represent a group selected from a hydrogen atom, alkyl group, aryl group and monovalent heterocyclic compound group; R 1 and R 2 each independently represent a group selected from alkyl group, alkoxy group, alkylthio group, alkylsilyl group, alkylamino group, aryl group, aryloxy group, arylsilyl group, arylamino group, arylalkyl group, arylalkoxy group, arylalkylsilyl group, arylalkylamino group, arylalkenyl group, arylalkynyl group, monovalent heterocyclic compound group and cyano group; m and n are each independently integers of 0 to 3; when m is two or more, a plurality of R 1 may be the same or different; when n is two or more, a plurality of R 2 maybe the same or different; R 1 to R 7 may be connected to form a ring; when R 1 to R 7 is a group containing an alkyl chain, the alkyl chain may be interrupted by a group containing a hetero atom, wherein R 8 represents a group selected from alkyl group, alkoxy group, alkylthio group, alkylsilyl group, alkylamino group, aryl group, aryloxy group, arylsilyl group, arylamino group, arylalkyl group, arylalkoxy group, arylalkylsilyl group, arylalkylamino group, arylalkenyl group, arylalkynyl group, monovalent heterocyclic compound group and cyano group; j is an integer of 0 to 3; when j is two or more, a plurality of R 8 may be the same or different; when R 8 is a group containing an alkyl chain, the alkyl chain may be interrupted by a group containing a hetero atom.