Browse Prior Art Database

Magneto-optic Disk Bulk Erase During Manufacture

IP.com Disclosure Number: IPCOM000099388D
Original Publication Date: 1990-Jan-01
Included in the Prior Art Database: 2005-Mar-14
Document File: 4 page(s) / 129K

Publishing Venue

IBM

Related People

McCarthy, RT: AUTHOR

Abstract

In order to write intelligent patterns of ones and zeros on a magnetooptic (MO) disk, the magnetic domains of the disk's magnetic material must have been previously preset to a known polarity.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Magneto-optic Disk Bulk Erase During Manufacture

       In order to write intelligent patterns of ones and zeros
on a magnetooptic (MO) disk, the magnetic domains of the disk's
magnetic material must have been previously preset to a known
polarity.

      During manufacture, the MO layer is deposited onto the disk's
surface forming the MO layer.  The magnetic domains of this layer are
deposited onto the disk's surface in a random pattern.  Currently,
the first-time user of a new magneto-optic disk formats the disk by
erasing the tracks of the magneto-optic layer one track at a time.
This puts the tracks of the magneto-optic layer into a known
polarity. The purpose of this disclosure is to eliminate this
track-by-track erasure, to save time, and to improve the disk's
signal-to-noise ratio.

      After a brief description of the layer of a magneto-optic disk,
dual- and single-sided construction, and the required magnetic field
polarity, this disclosure describes how the required magnetic field
polarity can be accomplished for single- and dual-sided MO disks
during the manufacturing process by bulk erasing the MO layer before
encapsulation into single- or dual-sided disks.

      Magneto-optic disks are constructed of several layers of
materials.  A typical dual-sided magneto-optic disk is shown in Fig.
1.  As can be seen, a dual-sided magneto-optic disk is constructed
from two single-sided disks which are bonded together.

      During the manufacturing phase the magneto-optic layer is
deposited on the reflective layer.  In examining the manufacturing
process at this time, one would find a series of single-sided
non-encapsulated magneto-optic disks.  These non-encapsulated disks
can have their magneto-optic layer polarized by bulk erasing the
total magneto-optic layer.

      Fig. 2, depicts a typical setup which provides for the bulk
erasing of the magneto-optic layer.  This is a...