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    1.
    发明专利
    未知

    公开(公告)号：DE69502234D1

    公开(公告)日：1998-06-04

    申请号：DE69502234

    申请日：1995-05-26

    Applicant: IBM

    Inventor： CALL DAVID ERNEST ,  FINKELSTEIN BLAIR IAN ,  JAQUETTE GLEN ALAN

    IPC: G11B7/00 ,  G11B7/0045 ,  G11B7/125

    Abstract: A write-once optical disk data recorder automatically calibrates a laser during a write data operation and using write pulses focussed to a disk. First, the laser is calibrated using a non-focussed laser beam. Each sector of the disk has a laser checking or test area, such as an automatic laser power correction field (ALPC) of two byte lineal extent. During a first write operation after a power up or disk load, a pulse width modulated (PWM) laser test signal is recorded using a laser power level set using the non-focussed laser beam and an indicated desired recording power level on the disk. The recorded laser test signal is read back. The length of the read back laser test signal is measured. The measured length is then compared with a desired length of the PWM laser test signal that indicates a desired laser power level. That is, as laser recording power levels increase, a resultant recorded signal grows in size. This property is used to measure laser power for calibrating laser operation.

    3.
    发明专利
    未知

    公开(公告)号：DE69502234T2

    公开(公告)日：1998-11-19

    申请号：DE69502234

    申请日：1995-05-26

    Applicant: IBM

    Inventor： CALL DAVID ERNEST ,  FINKELSTEIN BLAIR IAN ,  JAQUETTE GLEN ALAN

    IPC: G11B7/00 ,  G11B7/0045 ,  G11B7/125

    Abstract: A write-once optical disk data recorder automatically calibrates a laser during a write data operation and using write pulses focussed to a disk. First, the laser is calibrated using a non-focussed laser beam. Each sector of the disk has a laser checking or test area, such as an automatic laser power correction field (ALPC) of two byte lineal extent. During a first write operation after a power up or disk load, a pulse width modulated (PWM) laser test signal is recorded using a laser power level set using the non-focussed laser beam and an indicated desired recording power level on the disk. The recorded laser test signal is read back. The length of the read back laser test signal is measured. The measured length is then compared with a desired length of the PWM laser test signal that indicates a desired laser power level. That is, as laser recording power levels increase, a resultant recorded signal grows in size. This property is used to measure laser power for calibrating laser operation.

    4.
    发明专利
    未知

    公开(公告)号：DE69221049D1

    公开(公告)日：1997-09-04

    申请号：DE69221049

    申请日：1992-09-04

    Applicant: IBM

    Inventor： CALL DAVID ERNEST ,  LEWKOWICZ JULIAN

    IPC: G11B7/00 ,  G11B7/0045 ,  G11B7/0055 ,  G11B7/125 ,  G11B7/09 ,  H01S3/00

    Abstract: Method and apparatus for calibrating the drive current circuit of a semiconductor laser diode subject to reflected optical feedback from a target surface such an an optical recording disk. The method makes use of two power output vs. drive current characteristic curves for the laser, one curve 190 for in-focus condition and the other curve 191 for out-of-focus condition, wherein the curves exhibit an asymptotic region at high power level (P2). Measurement of drive current I2 at power level P2 is taken under an out-of-focus condition. Measurement of drive current I1 and I3 at a predetermined low power level P1 are taken for both out-of-focus condition and in-focus condition. The linear slope of the in-focus curve 190 can thus be calculated to set desired power levels.

    5.
    发明专利
    未知

    公开(公告)号：DE69221049T2

    公开(公告)日：1998-01-15

    申请号：DE69221049

    申请日：1992-09-04

    Applicant: IBM

    Inventor： CALL DAVID ERNEST ,  LEWKOWICZ JULIAN

    IPC: G11B7/00 ,  G11B7/0045 ,  G11B7/0055 ,  G11B7/125 ,  G11B7/09 ,  H01S3/00

    Abstract: Method and apparatus for calibrating the drive current circuit of a semiconductor laser diode subject to reflected optical feedback from a target surface such an an optical recording disk. The method makes use of two power output vs. drive current characteristic curves for the laser, one curve 190 for in-focus condition and the other curve 191 for out-of-focus condition, wherein the curves exhibit an asymptotic region at high power level (P2). Measurement of drive current I2 at power level P2 is taken under an out-of-focus condition. Measurement of drive current I1 and I3 at a predetermined low power level P1 are taken for both out-of-focus condition and in-focus condition. The linear slope of the in-focus curve 190 can thus be calculated to set desired power levels.

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