Optical information recording and reproducing apparatus including a

Abstract

An optical information recording and reproducing apparatus for effecting at least one of recording of information on and reproducing of information from a recording medium. The apparatus includes an optical system for applying a light beam to a desired track on the recording medium, a tracking and focusing error detection device for detecting tracking and/or focusing error of the light beam relative to the track, a computing unit for (i) receiving respective tracking error and focusing error output signals from the detecting device, (ii) effecting a computation for a selected output signal among the received output signals on the basis of a predetermined program to correct the detected tracking error and focusing error, (iii) calculating tracking and focusing control movement amounts and (iv) outputting a tracking control signal and a focusing control signal corresponding to the tracking control movement amount and the focusing control movement amount, respectively. The apparatus also includes a tracking actuator for moving at least a portion of the optical system to move the light beam relative to the track on the basis of the tracking control signal, and a focusing actuator for moving a portion of the optical system relative to the recording medium to adjust a focusing state of the light beam on the basis of the focusing control signal.