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Focus And Tracking Apparatus for Optical Disks

IP.com Disclosure Number: IPCOM000119942D
Original Publication Date: 1991-Mar-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 2 page(s) / 59K

Publishing Venue

IBM

Related People

Hancock, RA: AUTHOR [+2]

Abstract

An axially slideable focus unit is aligned with a laser beam directed to an optical disk. Track following or tracking is effected by a pivotal prism which reflects a laser beam into the focus mechanism. The prism has a mirror surface on one diagonal to reflect the beam.

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Focus And Tracking Apparatus for Optical Disks

      An axially slideable focus unit is aligned with a laser
beam directed to an optical disk.  Track following or tracking is
effected by a pivotal prism which reflects a laser beam into the
focus mechanism.  The prism has a mirror surface on one diagonal to
reflect the beam.

      An objective lens is slideably held to move for focussing
motions under control of a focus coil (Figure 1). The cylinder
slideably supports the lens support tube.  A prism is disposed at one
end of the cylinder and is pivoted for moving the laser beam in a
tracking or radial direction of a disk (not shown).  A preferred
support for the pivoted prism includes two permanent magnets on
opposite sides of the prism (Figure 2).  Four electric coils are
actuated by tracking control circuits (not shown) to pivot the mirror
for effecting tracking operations.  The base may be magnetically
permeable material.