Browse Prior Art Database

Multi-Lens Actuator for Optical Storage

IP.com Disclosure Number: IPCOM000117488D
Original Publication Date: 1996-Mar-01
Included in the Prior Art Database: 2005-Mar-31
Document File: 2 page(s) / 50K

Publishing Venue

IBM

Related People

Imaino, W: AUTHOR

Abstract

An apparatus for reading and writing an optical storage disk using an array of objective lenses attached to a coarse actuator, a means for directing light to individual lenses of the array, and actuators for fine tracking and focusing is disclosed. This apparatus, by decreasing the stroke required of the coarse actuator, allows lower access times and/or power consumption, reduces manufacturing cost, and allows a more global optimization of both tracking and focus actuation since the design of individual actuators is simplified. Fig. 1 shows an overview of the optical arrangement.

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Multi-Lens Actuator for Optical Storage

      An apparatus for reading and writing an optical storage disk
using an array of objective lenses attached to a coarse actuator, a
means for directing light to individual lenses of the array, and
actuators for fine tracking and focusing is disclosed.  This
apparatus, by decreasing the stroke required of the coarse actuator,
allows lower access times and/or power consumption, reduces
manufacturing cost, and allows a more global optimization of both
tracking and focus actuation since the design of individual actuators
is simplified.  Fig. 1 shows an overview of the optical arrangement.

      Light from the head optics passes through lens 1, which is
actuated to provide focus servo control; lens 3 and lens 4 are used
to ensure that all of the light reaches the objective lens array.
Galvo mirror (1) is used to provide fine tracking control, and galvo
mirror (2) with the field lens 4 is used to direct the light to the
individual lens elements of the actuated lens array.  The use of a
lens array reduces the required stroke and the only moving mass in
this arrangement is of the objective lenses themselves.  A paraxial
ray trace of an optical design for focus actuation on the stationary
optics is shown in Fig. 2.

      The symmetrical arrangement keeps the aperture of the objective
filled for all focus positions of the objective and in large part
cancels the spherical aberration if lenses 1 and 2 are identical to
the obj...