Dismiss
InnovationQ will be updated on Sunday, Oct. 22, from 10am ET - noon. You may experience brief service interruptions during that time.
Browse Prior Art Database

Dust-Trapping Lens Shield

IP.com Disclosure Number: IPCOM000120154D
Original Publication Date: 1991-Mar-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 2 page(s) / 113K

Publishing Venue

IBM

Related People

Yanker, GM: AUTHOR

Abstract

Prevention of dust contamination on the laser optic surfaces (lenses and mirrors) of a CDROM (Compact Disc Read Only Media) device has become an important aspect of CDROM reliability. One marketplace solution is a snap-on cover or shield which has an opening only where the laser beam passes through an upper lens to reflect off the media.

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

Dust-Trapping Lens Shield

      Prevention of dust contamination on the laser optic
surfaces (lenses and mirrors) of a CDROM (Compact Disc Read Only
Media) device has become an important aspect of CDROM reliability.
One marketplace solution is a snap-on cover or shield which has an
opening only where the laser beam passes through an upper lens to
reflect off the media.

      A further solution in the marketplace involves various types of
brush-type cleaning devices to brush dust off the lens surface,
located just inside the opening of the cover or shield.
Unfortunately, the use of such brush-type devices also can sweep dust
(which also accumulates on the outside surface of the shield near the
opening) toward and into the shield opening.  So this brushing action
can also increase the amount of dust allowed inside the otherwise
protective cover or shield, where there are other optical surfaces
which cannot be cleaned without some disassembly of the device.

      Two types of cleaning discs are avilable which can be called
type "A" and type "B".  Type "A" has a brush on the bottom side which
does not rotate, but stays stationary relative to the disc "caddy"
which contains the laser disc. So installing and removing the special
caddy causes its brush to wipe across shield and the upper lens
surface in a front-to-rear direction.  Type "B" has a brush attached
to the bottom of a rotating cleaning disc so that it sweeps across
the upper surface of the shield and the upper lens in a
circumferential arc.  Both type "A" and "B" devices use brushes which
clean only the shield and the upper surfaces of the upper lens.  The
laser beam passes through three other optical surfaces down below
which are not cleaned by the cleaning discs, so that the original
signal through the optic system is never fully restored by the use of
either cleaning disc, and repeated cleaning-disc operations are less
and less effective.

      Two types of cleaning discs are available.  The first type has
a brush on the bottom side which does not rotate, but stays
stationary relative to the disc "caddy" which contains the laser
disc.  So installing and removing the special caddy causes its brush
to wipe across the shield and the upper lens surface in a
front-to-rear direction.  The second type has a brush attached to the
bottom of a rotating cleaning disc so that it sweeps across the upper
surface of the shield and the upper lens in a circumferential arc.
Both types use brushes which clean only the shield and the upper
surface of the upper lens.  The laser beam passes through three other
optical surfaces down below which are not cleaned by the cleaning
discs, so th...