An optical information recording and information reproducing - / - reproducing apparatus with digital servo device for focusing and / or for an optical head tracking, based on digital information

摘要

An optical information recording/reproducing apparatus for recording and/or reproducing information on and/or from an optical memory medium (1) includes an optical system (2) for forming a light beam spot for recording and/or reproducing information on and/or from the optical memory medium, a signal generating unit (3,4) for detecting a position of the optical system relative to the medium and generating an analog signal corresponding to the detected position, an actuator (12,13) for driving the optical system, an A/D converter (5) for converting the analog signal from the signal generating unit into a digital signal, a digital signal processing unit (16) for calculating a control amount of the actuator on the basis of a predetermined control process in order to correct the relative position from an output from the A/D converter, and a D/A converter (11) for converting the output from the digital signal processing unit into an analog signal. The actuator is driven in correspondence with the output from the D/A converter. The control process of the digital signal processing unit can be arbitrarily changed.