PHOTODETECTOR FOR DETECTING TRACKING ERROR, DEVICE AND METHOD FOR DETECTING TRACKING ERROR, DEVICE AND METHOD FOR DETECTING FOCUSING ERROR AND OPTICAL HEAD FOR MAGNETO-OPTICAL RECORDING/REPRODUCING

摘要

PURPOSE:To reduce the inclination of the radial direction of a magneto-optical disk and DC offset generating at a tracking error signal caused by the movement of the tracking direction of an objective lens when a tracking error is detected by utilizing a push-pull method. CONSTITUTION:A quinquepartite photodiode is used as a photodetector for detecting a tracking error 21. The tracking error signal is generated by difference between the signals outputted by the photodiodes 21b and 21c among the photodiodes 21a-21e. By providing two photodetectors 21 and 22, a focusing error signal is also generated by utilizing a beam size method.