公开(公告)号：DE69116039T2

公开(公告)日：1996-07-04

申请号：DE69116039

申请日：1991-03-01

Applicant: IBM

Inventor： FINKELSTEIN BLAIR IAN ,  TAYEFEH MOROVAT ,  UENO HIDEO

IPC: G11B7/00 ,  G11B7/0045 ,  G11B7/0055 ,  G11B7/125 ,  G11B11/10 ,  G11B11/105 ,  G11B20/18 ,  G11B27/36

Abstract: The present invention relates to a method of calibrating a system for the recording and readback of optically detectable data of the type which comprises a record medium (30) formed from a material which is sensitive to optical radiation, means (67) for generating a beam of light (47), means (33) for scanning the beam of light relative to the surface of the medium, means (75) for selectively varying the intensity of the beam of light so as to record data at selected positions on the surface and means (79) for reading back the recorded data. The calibrating method comprises the operation of controlling the recording intensity of the beam of light so that signals from the readback means have a maximum amplitude. According to the invention the operation of controlling the recording intensity comprises utilising the beam of light to record a plurality of test patterns (29) on the surface of the medium each pattern being recorded with a different intensity of the beam of light, reading back the test patterns and generating a readback test signal from each test pattern, detecting the readback test signal having the largest amplitude, and utilising the intensity of the beam of light used to record the test pattern which generates the readback test signal having the largest amplitude for the light beam when it is recording data. The invention also relates to apparatus for implementing the above method of calibrating.

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.

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.

公开(公告)号：DE69027665D1

公开(公告)日：1996-08-08

申请号：DE69027665

申请日：1990-12-17

Applicant: IBM

Inventor： FINKELSTEIN BLAIR IAN ,  MC DANIEL TERRY WAYNE

IPC: G11B7/135 ,  G11B7/005 ,  G11B7/09 ,  G11B11/10 ,  G11B11/105

公开(公告)号：DE69116039D1

公开(公告)日：1996-02-15

申请号：DE69116039

申请日：1991-03-01

Applicant: IBM

Inventor： FINKELSTEIN BLAIR IAN ,  TAYEFEH MOROVAT ,  UENO HIDEO

IPC: G11B7/00 ,  G11B7/0045 ,  G11B7/0055 ,  G11B7/125 ,  G11B11/10 ,  G11B11/105 ,  G11B20/18 ,  G11B27/36

Abstract: The present invention relates to a method of calibrating a system for the recording and readback of optically detectable data of the type which comprises a record medium (30) formed from a material which is sensitive to optical radiation, means (67) for generating a beam of light (47), means (33) for scanning the beam of light relative to the surface of the medium, means (75) for selectively varying the intensity of the beam of light so as to record data at selected positions on the surface and means (79) for reading back the recorded data. The calibrating method comprises the operation of controlling the recording intensity of the beam of light so that signals from the readback means have a maximum amplitude. According to the invention the operation of controlling the recording intensity comprises utilising the beam of light to record a plurality of test patterns (29) on the surface of the medium each pattern being recorded with a different intensity of the beam of light, reading back the test patterns and generating a readback test signal from each test pattern, detecting the readback test signal having the largest amplitude, and utilising the intensity of the beam of light used to record the test pattern which generates the readback test signal having the largest amplitude for the light beam when it is recording data. The invention also relates to apparatus for implementing the above method of calibrating.

公开(公告)号：CA2046704C

公开(公告)日：1995-09-26

申请号：CA2046704

申请日：1991-07-10

Applicant: IBM

Inventor： FENNEMA ALAN AUGUST ,  FINKELSTEIN BLAIR IAN ,  TAYEFEH MOROVAT ,  YARDY RAYMOND

IPC: G11B7/00 ,  G11B7/004 ,  G11B7/0045 ,  G11B7/085 ,  G11B7/09 ,  G11B7/125 ,  G11B11/10 ,  G11B11/105 ,  G11B19/12 ,  G11B27/19

Abstract: An optical disk recorder is capable of operating with diverse types of optical media. An device initialization procedure is repeated for each receipt of each optical medium. Such procedure includes moving a objective lens to an extreme radial position, defocussing the lens at a most remote position, then calibrating the laser circuits to ensure that the emission of radiation from the laser will not inadvertently destroy signals recorded on the just received medium. Then the medium type is read from the medium and based upon the type indication, various additional calibrating procedures are followed and different sources of laser control values are used for signal exchanging operations between the recorder and received optical medium.