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Magnetic Field Shield Apparatus

IP.com Disclosure Number: IPCOM000114576D
Original Publication Date: 1995-Jan-01
Included in the Prior Art Database: 2005-Mar-29
Document File: 2 page(s) / 47K

Publishing Venue

IBM

Related People

Hirasaka, Y: AUTHOR [+4]

Abstract

This article describes a Magnetic field shield apparatus for VCM of magneto-optical disk drive. Which has apertures to reduce magnetic interference between VCM and itself. By reducing it, the power source of mechanical resonance of carriage (5) can be removed.

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Magnetic Field Shield Apparatus

      This article describes a Magnetic field shield apparatus for
VCM of magneto-optical disk drive.  Which has apertures to reduce
magnetic interference between VCM and itself.  By reducing it, the
power source of mechanical resonance of carriage (5) can be removed.

      The Figure shows the example of this apparatus.  Generally,
magneto-optical disk drives have VCM (4) as a method of seeking and
tracking.  It yields strong magnetic field around itself.  At the
same time, permanent-magnet type bias magnet (9) sometimes is used.
This bias magnet uses magnetic field as a power source of rotating
itself for switching erase/write mode as well as supplying the bias
magnet field for media.  In this case, in order to reduce the
interference of magnetic field to bias magnet, it requires to use a
Magnetic Field Shield (7).  At the same time, this Magnetic Field
Shield (7) protects shafts (6) from iron particles and other magnetic
materials contamination, because its material has ferromagnetism.
But it has a side effect.  The Magnetic Field Shield (7) changes the
magnetic shield.  And with this irregular magnetic loop, carriage (5)
sometimes has resonance.  As a result of this effect, magneto optical
disk drive has bad performance in seeking process or tracking
process.  To reduce this effect, this apparatus has an apertures (8)
at the top of VCM gap and apertures are filled with diamagnetism
material.