Optical information recording apparatus
A rewritable optical disk apparatus, optical information recording and reproducing apparatus or the like is allowed to automatically and properly adjust the optical system to the optimum focal condition regardless of the readout signal detector's positional error and the residual aberration in the optical system. The spherical aberration and defocus are coarsely adjusted using the amplitude (PP amplitude) of the tracking error signal and then finely adjusted using the amplitude (RF amplitude) of the readout signal. Since the spherical aberration can properly be adjusted, it is possible to raise the reliability of the readout signal.
1. An optical information recording apparatus which optically reads and writes information from and to a recording medium, comprising:
a first detector for detecting amplitude of a readout signal;
a second detector for detecting amplitude of a tracking error signal;
a first adjustor for adjusting spherical aberration;
a second adjustor for adjusting defocus of an objective lens;
an oblique search means for changing the spherical aberration and the defocus obliquely in a two-dimensional rectangular coordinate system whose respective axes represent the defocus and the spherical aberration;
a rectangular search means for changing the spherical aberration and the defocus rectangularly in the two-dimensional rectangular coordinate system; and
a switching means for switching the oblique search means and the rectangular search means when adjusting coarsely and finely;
wherein:
the spherical aberration and the defocus are adjusted at first obliquely by the oblique search means so as to maximize the amplitude of the tracking error signal and then adjusted rectangularly by the rectangular search means so as to maximize the amplitude of the readout signal,
the recording medium is a non-rotary recording medium,
said apparatus further comprises a memory for storing optimum spherical aberration values and optimum defocus values which are respectively for four corners on the recording medium, and
the optimum spherical aberration and defocus values for an information read/write position are calculated from the stored optimum values by interpolation based on ratios in terms of distances from the four corners.
2. An optical information recording apparatus according to claim 1 , wherein:
in case that an initialized recording medium is inserted, the adjustment is started from optimization for the amplitude of the readout signal; and
in case that a not initialized recording medium is inserted, the adjustment is started from optimization for the amplitude of the tracking error signal.
3. An optical information recording apparatus which optically reads and writes information from and to a recording medium, comprising:
a first detector for detecting amplitude of a readout signal;
a second detector for detecting amplitude of a tracking error signal;
a first adjustor for adjusting spherical aberration;
a second adjustor for adjusting defocus of an objective lens;
an oblique search means for changing the spherical aberration and the defocus obliquely in a two-dimensional rectangular coordinate system whose respective axes represent the defocus and the spherical aberration; and
a rectangular search means for changing the spherical aberration and the defocus rectangularly in the two-dimensional rectangular coordinate system;
wherein the spherical aberration and the defocus are adjusted by the oblique search means so as to maximize the amplitude of the tracking error signal from an unrecorded rewritable optical recording medium, marks are recorded on the optical recording medium, and then the spherical aberration and the defocus are adjusted by the rectangular search means so as to maximize the amplitude of the readout signal,
wherein the recorded marks constitute a repetitive pattern whose mark interval is 2 to 4 times a track interval in a data area.