Patent ID: 7122134

Claim:
An optical member comprising a region having a distribution in the refractive index, formed by polymerization of a composition comprising a polymerizable monomer and a compound represented by formula (1) below having a refractive index differing from that of the polymerizable monomer: where R 1 and R 3 independently denote a C1–12 atkyl group, a C3–6 cycloalkyl group, a halogen atom, CH 2 ═CH—, CH 2 ═CH—O—, CH 2 CH—C(═O)—O—, CH 2 ═C(CH 3 )—C(═O)O—, R 4′ —C(═O)O—, R 4′ —C(═S)O—, R 4′ —C(═O)— or R 4′ —O— where R 4 denotes a C1–9 alkyl group, provided that at most a single one of the collective plural R 1 and plural R 3 groups represents a polymerizable group selected from the group consisting of CH 2 CH—, CH 2 ═CH—O—, CH 2 ═CH—C(═O)—O—, and CH 2 ═C(CH 3 )—C(═O)O—; l and n are respectively integers of 0 to 5, provided that at least one of l and n is not 0; and u is an integer of 0 to 2.