Light spot positioning method and optical disc memory apparatus employing the same

A light spot positioning method comprising the steps of performing a seek operation of positioning a record/playback light spot at a desired track on a recording medium by a macro moving mechanism for an optical head and a micro moving mechanism comprising a non-mechanical optical deflector mounted on one of said optical head and a base of a record/playback apparatus, and wobbling the light spot projected from said optical head from an initial position thereof to each side of said track by said micro moving mechanism to detect a track error signal from a difference between resulting reflected light quantities, wherein an interval Ti of a wobbling period of said light spot is selected to be Ti<1/(3-2.pi.fcf) with respect to a bandwidth fcf of a control servo of said micro moving mechanism.

A light spot positioning method comprising the steps of performing a seek operation of positioning a record/playback light spot at a desired track on a recording medium by a macro moving mechanism for an optical head and a micro moving mechanism comprising a non-mechanical optical deflector mounted on one of said optical head and a base of a record/playback apparatus, and wobbling the light spot projected from said optical head from an initial position thereof to each side of said track by said micro moving mechanism to detect a track error signal from a difference between resulting reflected light quantities, wherein an interval Ti of a wobbling period of said light spot is selected to be longer during a track following operation than during a track pull-in operation.

A light spot positioning method comprising the steps of performing a seek operation of positioning a record/playback light spot at a desired track on a recording medium by a macro moving mechanism for an optical head and a micro moving mechanism comprising a non-mechanical optical deflector mounted on one of said optical head and a base of a record/playback apparatus, and wobbling the light spot projected from said optical head from an initial position thereof to each side of said track by said micro moving mechanism to detect a track error signal from a difference between resulting reflected light quantities, wherein an interval Ti of a wobbling period Tw of said light spot is selected to be the same as the wobbling period Tw of said light spot during a track pull-in operation.

A light spot positioning method comprising the steps of performing a seek operation of positioning a record/playback light spot at a desired track on a recording medium by a macro moving mechanism for an optical head and a micro moving mechanism comprising a non-mechanical optical deflector mounted on one of said optical head a base of a record/playback apparatus, generating a track error signal based on reflected light from the recording medium of the light spot, and wobbling the light spot projected from said optical head from an initial position thereof to each side of the radial direction of said track by said micro moving mechanism, holding the track error signal at each side of said track, calculating sum of the track error signals at each side of said track, subtracting one half (1/2) of said sum from an initial track error signal to generate an offset-free track error signal, and simultaneously producing a difference between said track error signals resulting from said wobbling to generate an offset-free cross track signal having a 90-degree phase difference from said offset-free track error signal.

A light spot positioning method comprising the steps of performing a seek operation of positioning a record/playback light spot at a desired track on a recording medium by a macro moving mechanism for an optical head and a micro moving mechanism comprising a non-mechanical optical deflector mounted on one of said optical head and a base of a record/playback apparatus, generating a track error signal based on reflected light from the recording medium of the light spot and wobbling the light spot projected from said optical head to each side of the radial direction of said track from an initial position thereof be said micro moving mechanism so that an offset-free track error signal is produced from a difference between resulting total reflected light quantities of the light spot projected onto said recording medium, holding the track error signal at each side of said track and simultaneously producing a sum of the total reflected light quantities of the track error signal at each side of said track and subtracting one half (1/2) of said sum from the total reflected light quantity of said initial position to generate an offset-free cross track signal having a 90-degree phase difference from said offset-free track error signal.