HIGH DENSITY OPTICAL RECORDER

摘要

PROBLEM TO BE SOLVED: To provide a high density optical recorder that employs a light receiving element whose light receiving face is multiply divided (a photo diode array or a charge coupled device(CCD)) in a collimate optical system to detect a reflected optical image of a light focused around a tip of a probe and applies calculation processing to the obtained reflected image with a correlation arithmetic operation so as to independently detect a deviation in the focal depth thereby applying feedback control to the focal depth. SOLUTION: Even in a near field probe where the optical distribution of a reflected image causes asymmetry due to focal position deviation in 3 axis directions a deviation in the focal depth can be detected independently of a deviation in a direction perpendicularly to the focal depth. Since the probe can detect the focal deviation in the collimate optical system, the optical mechanism can be simplified and no delicate position adjustment of a photo detector is required.