Optical Pickup Unit and Optical Pickup Device Having Same and Information Writing/Reading Device Having Same

摘要

An optical pickup device includes: a splitting section for splitting a beam; a light-receiving section for receiving the split beams. The light-receiving section includes: a tracking-use main light-receiving region and tracking-use sub light-receiving regions, and auxiliary light-receiving regions. Each of the auxiliary light-receiving regions receives only a light beam reflected off a recording layer other than a recording layer subjected to an information writing/reading process. A light-receiving area of each of the auxiliary light-receiving area is smaller than a light-receiving area of each tracking-use light-receiving region. Further, an optical pickup device includes: a splitting section for splitting a beam; and a light-receiving section for receiving the split beams. The light-receiving section includes a sub light-receiving regions for receiving tracking-use sub beams. The tracking-use sub beams are arranged so as not to allow entering of a focusing-use main beam reflected off a non-targeted recording layer.