Browse Prior Art Database

Dust Entrapment Design for Optical Path

IP.com Disclosure Number: IPCOM000108501D
Original Publication Date: 1992-Jun-01
Included in the Prior Art Database: 2005-Mar-22
Document File: 3 page(s) / 102K

Publishing Venue

IBM

Related People

Yanker, GM: AUTHOR

Abstract

Described herein is a method for increasing tolerance to contaminating dust particles in an optical compact disc drive, such as a CD-ROM or other dust-sensitive device.

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

Dust Entrapment Design for Optical Path

       Described herein is a method for increasing tolerance to
contaminating dust particles in an optical compact disc drive, such
as a CD-ROM or other dust-sensitive device.

      A state-of-the-art CD-ROM has a cover or shield as a partial
barrier to contamination of its optical system. However dust gets in
through the aperture in the lens cover, penetrates further into the
inner optical system, and contaminates the interior functional
laser-optic surfaces. This causes premature failure of CD-ROM drives
and of similar optical equipment.  Using boundary entrapment, passive
collection of dust can be achieved in areas where classical air
filtration methods cannot be deployed.

      Referring to Fig. A, because the lens opening 1 in an optical
shield 2 cannot be closed over or sealed, airborne contamination
particles can enter through the lens opening 1.  Below this opening
is a movable upper lens 3 which is mounted to move vertically on a
four-bar linkage 4 and also pivoted (not shown) to swing or rotate
horizontally.  This movement tends to keep the contaminated air in
motion, and dust particles have many opportunities to collide with
and deposit upon both functional (optical) and non-functional
(non-optical) surfaces.  Below this movable upper lens 3 is a
stationary mirror 5 which deflects the laser beam approximately 90
degrees into a horizontal light tube 8. Contamination (dust) which
enters through lens opening 1 finds essentially no seal or barrier
between itself and the interior optical surfaces.  Therefore, optical
contamination occurs and de grades the laser-optical signal at the
three exposed optical surfaces which are the bottom side 3B of the
upper lens 3, the mirror 5, and the face 7 of the light tube 8.
Only the upper surface 3A of the upper lens 3 is cleanable by the
device operator, by using a commercially-available cleaning disk that
b...