Optical pickup device and focus control method therefor

Abstract

An optical pickup device comprises a first laser light source and a second laser light source that emit first laser light and second laser light, respectively, and further comprises an objective lens that receives the first and second laser light. The first laser light and the second laser light have different focal lengths from a principal point of the objective lens in accordance with a distance between a signal layer of a signal recording medium and a label layer of the signal recording medium. When the first laser light source and the second laser light source are simultaneously driven, the first laser light and the second laser light are controlled to simultaneously focus on the signal layer of the signal recording medium and the label layer of the signal recording medium, respectively. Thus, label information can be recorded simultaneously with recording of main information.