公开(公告)号：JPH04134737A

公开(公告)日：1992-05-08

申请号：JP25546890

申请日：1990-09-27

Applicant: IBM

Inventor： SOTOZONO KAZUO ,  SHINOHARA TATSUOKI ,  TOKIZONO AKIRA ,  UENO SHIGEO

IPC: G11B7/125 ,  G11B7/126

Abstract: PURPOSE: To enable a laser output to be set at the optimum value by determining such a digital value for setting an output as the laser output of a write mode is equal to that of a read mode and, on the basis of this value, deciding such a digital value for setting an output as a desired laser output is generated under the write mode. CONSTITUTION: A laser output from a laser diode 10 is detected by a light- quantity detector 16 and imparted in parallel to a voltage differential detector 18 and an analog-digital converter 20. The voltage differential detector 18, comparing this detected value with a reference voltage, imparting a voltage output in accordance with the comparison result to a driving circuit 26 through a switching circuit 24. In a read mode, the laser output is controlled so that the detection voltage of the light-quantity detector 16 is always equal to the reference voltage generated by a reference voltage generating circuit 22. Then, a digital value which generates a laser output equal to this reading power is detected and, on the basis of this value, a digital value which generates a desired laser output is determined. As a result, the laser output is set at the optimum value.

公开(公告)号：JPH04139669A

公开(公告)日：1992-05-13

申请号：JP25546990

申请日：1990-09-27

Applicant: IBM

Inventor： KAGAMI NAOYUKI ,  KUBO HIROAKI ,  UENO SHIGEO

IPC: G11B21/08 ,  G11B7/085 ,  G11B7/09

Abstract: PURPOSE: To surely position an optical disk driving device even if an optical disk is inclined by adding/reducing speed of an optical pickup with the use of a tracking error signal. CONSTITUTION: An optical pickup 3 is moved outward after it is pressed to a position where no track guiding groove is formed inside an optical disk 5. Then, a tracking error signal is detected by a tracking sensor 15, with a track counter 21 calculating the number of crossing of the track guiding groove. The crossing state is monitored for the pickup 3 of the track guiding groove by constantly checking this discrete value, so that an adding/reducing/stopping control of the pickup 3 is carried out by CPU 20. Accordingly, without detecting the absolute position using a scale, the initial adjustment of the optical pickup is performed well by surely positioning the disk driving device without complicating the structure even when the pickup is inclined.

公开(公告)号：JPH05189827A

公开(公告)日：1993-07-30

申请号：JP1220491

申请日：1991-02-01

Applicant: IBM

Inventor： BURAIAA AIAN FUINKERUSUTAIN ,  MOROBATSUTO TAIEFUEE ,  UENO SHIGEO

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

Abstract: PURPOSE: To provide a calibration method and device thereof for making the power level of a laser suitable for writing to a magneto-optical recording medium to the sensitivity of the medium. CONSTITUTION: One of calibration tracks fixed in the direction of the diameter of a magneto-optical disk 30 is selected, and the selected track is erased with high power by a laser device 67 under the control of a control circuit 66, and one test pattern is repeatedly written in the selected tracks by using plural different levels. Then a recorded test pattern is read to envelope-detect the amplitude of the read signal, and a microprocessor 40 prepares a table expressing a signal envelope and applies the envelope to the curve. Based on the curve, a maximum reading signal amplitude is detected to detect laser power for writing by which the maximum amplitude is obtained, to make the power reference for laser power for actual writing and designating laser power for erasing.