Browse Prior Art Database

Index Matching Lube for Optical Storage

IP.com Disclosure Number: IPCOM000113167D
Original Publication Date: 1994-Jul-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 36K

Publishing Venue

IBM

Related People

Rugar, D: AUTHOR [+2]

Abstract

Disclosed is the use of an index matching lube for use with a flying Solid-Immersion Lens (SIL). In addition to its usual role in aiding in the flying of a slider in close proximity to a disk, the lube also serves as an optical index-matching media between the SIL and the disk.

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This is the abbreviated version, containing approximately 85% of the total text.

Index Matching Lube for Optical Storage

      Disclosed is the use of an index matching lube for use with a
flying Solid-Immersion Lens (SIL).  In addition to its usual role in
aiding in the flying of a slider in close proximity to a disk, the
lube also serves as an optical index-matching media between the SIL
and the disk.

      By focusing light rays through a SIL made from a high index of
refraction (n) material, the focused spot size can be reduced in
diameter by a factor of n(2)  over that obtained without the SIL.
The SIL consists of a truncated sphere of height r(1 + 1/n), where r
is the radius of the sphere [*].  When the SIL is incorporated into
an optical data storage device, the potential data density is
increased by a factor of n(4).  The SIL would be placed between a
focusing objective and the media and must be maintained at a distance
of much less than the wavelength of light from the media surface.

      To achieve this close spacing of the SIL to the media, the SIL
would be mounted onto a slider, similar to those used in magnetic
recording.  To aid in the flying of the SIL at such low fly heights,
a lubricated disk would be beneficial.  By use of a lube with a high
index of refraction, the lube can also serve as an index-matching
fluid between the SIL and disk.  This would maintain the small
focused spot size of the SIL across the SIL-to-disk spacing.  The
lube could either be confined to a several nanometer thick layer,
such as used in...