Patent ID: 7282160

Claim:
A light emitting device comprising a semiconductor light emitting element which emits light within the region from near-ultraviolet light to visible light, and a fluorescent material which contains a rare earth element ion complex having an aromatic ring-containing Bronsted acid ion with a pKa value of 7 or less as a ligand and emits light by the action of light of said semiconductor light emitting element, wherein a Bronsted acid ion represented by general formula (2) shown below, which is derived from an aromatic ring-containing Bronsted acid represented by general formula (1) shown below, is used as said ligand wherein R 1 is a group containing at least one aromatic hydrocarbon ring or aromatic heterocycle, each optionally having a substituent group at less than all available positions, X is a divalent connecting group, Q represents a carbon, sulfur or phosphorous atom, a represents 1 or 2, n represents 0 or 1, and p represents 0 or 1, and wherein when said Bronsted acid is an optionally substituted benzophenone carboxylic acid, the carboxylic acid group lies at an ortho position relative to the carbonyl group.