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Improved (Low Vibration) Double-Sided Optical Write-Once-Read-Many Recording Disk

IP.com Disclosure Number: IPCOM000115843D
Original Publication Date: 1995-Jun-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 2 page(s) / 91K

Publishing Venue

IBM

Related People

Belser, K: AUTHOR [+2]

Abstract

Through use of a constrained layer damping mechanism, the vibration amplitudes of Double-Sided (DS) optical Write-Once-Read-Many (WORM) disks can be reduced. Vibrations of the disk, caused by internal or external disturbances to the drive, can cause Focus Mis-Registration (FMR) problems for the laser beam. This then results in degraded read/write performance of the data. It is therefore desirable to reduce the amplitude of any vibrations that are induced on the disk. As mentioned, this can be achieved by adding a damping mechanism to the disk.

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Improved (Low Vibration) Double-Sided Optical Write-Once-Read-Many
Recording Disk

      Through use of a constrained layer damping mechanism, the
vibration amplitudes of Double-Sided (DS) optical
Write-Once-Read-Many (WORM) disks can be reduced.  Vibrations of the
disk, caused by internal or external disturbances to the drive, can
cause Focus Mis-Registration (FMR) problems for the laser beam.  This
then results in degraded read/write performance of the data.  It is
therefore desirable to reduce the amplitude of any vibrations that
are induced on the disk.  As mentioned, this can be achieved by
adding a damping mechanism to the disk.

      A common method of damping structures is through the use of the
constrained-layer damper mechanism.  Double-sided optical media lends
itself to this mechanism since the two disk substrates can be used as
the relatively stiff constraining layers.  A relatively soft
visco-elastic material placed between the two disks completes the
constrained-layer damper mechanism.  The natural modes of vibration
of the disk assembly create relative radial motion between the two
disks, which in turn shears the visco-elastic (damping) material.
The shear strain induced in the damping material dissipates the
vibrational energy of the system.

      Currently, double-sided WORM media is made by bonding two
single-sided disks in a back-to-back arrangement with spacers at the
inner diameter ID) and Outer Diameter (OD) to provide the necessary
air gap between the disks in the data recording region.  These
spacers...