公开(公告)号：JP2002260355A

公开(公告)日：2002-09-13

申请号：JP2001052643

申请日：2001-02-27

Applicant: IBM

Inventor： HATTORI RYOHEITA ,  MATSUBARA NOBUYA ,  KOKUBO TETSUYA ,  UMEMURA KAORU ,  KAGAMI NAOYUKI

IPC: G11B21/10 ,  G11B19/04 ,  G11B20/18 ,  G11B27/36 ,  G11B33/10

Abstract: PROBLEM TO BE SOLVED: To improve the reliability of a burst pattern inspection in a hard disk drive. SOLUTION: The writing test of test pattern data on a track boundary is added besides the writing of a test pattern in a SAT test at the track center conventionally performed and the inspection of burst patterns (A, B patterns) by the writing test at that time. Thereby, a highly sensitive inspection of C and D burst patterns sensitive to a PES signal can be conducted on the track boundary.

公开(公告)号：JPH04232654A

公开(公告)日：1992-08-20

申请号：JP19991591

申请日：1991-07-16

Applicant: IBM

Inventor： HENRII EDOWAADO ABIRESU ,  EDOUIN RARUFU CHIYAIRUDAAZU ,  KOKUBO TETSUYA ,  MATSUSHITA HIROSHI ,  DEBITSUDO POORU EMUSHII REINOR ,  MINAMIYA KOUICHIROU

IPC: G11B7/095 ,  G11B19/20 ,  G11B21/10 ,  G11B33/08 ,  G11B33/12

Abstract: PURPOSE: To prevent instability in a servo control system in an optical disk drive by shifting a feedback phase by 180 deg. and mechanically feedback controlling. CONSTITUTION: A rough actuator 16 provided with a carriage 15 for controlling tracking movement of a read/write head 12 is attached to the base 11, of the optical disk drive 10. The actuator 16 is provided with a voice coil 23, etc., and a precise actuator 14 controlling focusing of an objective lens 13 also, and the actuator 14 is feedback controlled mechanically through a circuit card 21. The feedback phase is shifted by 180 deg. by the opening of the base 11 and a bend member of a spindle attaching flange, and reduction in a phase margin is eliminated. Thus, the instability in the servo control system is prevented, and the optical disk drive capable of stably controlling a mechanical servo without harmful resonance occurrence, etc., is obtained.