Error signal detection apparatus and reproduction signal detection apparatus for optical recording/reproducing system

摘要

An error signal detection apparatus for an optical recording/reproducing system, which includes: a photodetector (30) having eight light receiving portions arranged in a 2×4 matrix, to separately perform photoelectric conversion on light reflected and diffracted from the recording medium, where the eight light receiving portions include four inner light receiving portions (A2,B2,C2,D2) arranged at the center region of the photodetector, and four outer light receiving portions (A1,B1,C1,D1) arranged around the corresponding inner light receiving portions; and a circuit unit (50) that compares the phases of the detection signals of the inner and/or outer light receiving portions arranged in the same row, and outputs a tilt error signal and/or tracking error signal from phase comparison signals. Other embodiments employ other circuit arrangements, including using diagonally opposite signal pairs. Tracking and/or tilting can be more precisely controlled even for a high-density recording medium having narrow tracks.