Browse Prior Art Database

Self-Servo Writing Method

IP.com Disclosure Number: IPCOM000102075D
Original Publication Date: 1990-Oct-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 3 page(s) / 83K

Publishing Venue

IBM

Related People

Ono, H: AUTHOR

Abstract

Disclosed is an improved method of the Japanese Published Unexamined Patent Application 02-156467 which has two (pre and post) servo writing stages to reduce clean room occupation. The improvement comprises a master servo pattern feature at the pre-stage and a center offset cancelling method at the post-stage to eliminate any fine mechanical part in a post-writer. a. Pre-stage

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Self-Servo Writing Method

       Disclosed is an improved method of the Japanese Published
Unexamined Patent Application 02-156467 which has two (pre and post)
servo writing stages to reduce clean room occupation.  The
improvement comprises a master servo pattern feature at the pre-stage
and a center offset cancelling method at the post-stage to eliminate
any fine mechanical part in a post-writer.
      a. Pre-stage

      The master disk pattern shown in Fig. 1 is different from that
disclosed in the Published Application 02-156467. The master pattern
has several tens of sectors in which both the clock pattern and
position pattern are written. Usually, the number of sectors is
determined as a multiple of the product sector number.  The master
tracks are written almost fully from an outer side to an inner side
over the disk surface.
      b. Post-stage

      After a disk file has been assembled, an actuator is pushed to
an outer guard or an inner guard by the constant force of adequate
VCM (voice coil motor) current.  Then the center of the master track
circle is measured by reading the master servo pattern with a head
provided at the guard in the file.  The detected data are stored in a
table in registers or a memory. (Refer to Fig. 2.)  The actuator
position is controlled by a sample servo system by referring to the
master pattern and driving the VCM provided in the file. Then, proper
servo track courses whose centers are the same as that of a...