| 摘要 |
PURPOSE:To surely perform high-density additional recording with two optical beams, by using a polariscope and track grooves which allow recording by discontinuously increasing sector numbers as moving from the inner periphery of a disk to the outer periphery. CONSTITUTION:A waveform which changes at a 0.3-MHz step from 60MHz to 90MHz can be stabilized with high accuracy by controlling a program with a microcomputer. When the variable frequency of an oscillator 16 is changed by a frequency corresponding to a track pitch 1.6mum at every one rotation of a disk, the reflecting light of an optical spot 9 is received by a photodetector 13. Upon receiving the reflecting light, a tracking error signal is outputted for tracking a reference track 11 deg. and a lens actuator is driven so that the optical spot 9 tracks the reference track 11 deg.. On the other hand, a variable diffracted wave 6 used for making data recording is set to the track pitch at every one rotation of the disk and deflected by a quantity corresponding to 6mum, and then, recorded by maintaining a fixed track pitch by another optical spot 8. Therefore, high- density additional recording can surely be performed. |
