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Browse Prior Art Database

Improved Flexure-Type Fine Actuator

IP.com Disclosure Number: IPCOM000105063D
Original Publication Date: 1993-Jun-01
Included in the Prior Art Database: 2005-Mar-19
Document File: 6 page(s) / 115K

Publishing Venue

IBM

Related People

Aviles, H: AUTHOR [+2]

Abstract

Flexure-type fine actuators are often used in optical storage drives to keep the laser beam centered on a data groove and focused properly on the media surface.

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This is the abbreviated version, containing approximately 59% of the total text.

Improved Flexure-Type Fine Actuator

      Flexure-type fine actuators are often used in optical storage
drives to keep the laser beam centered on a data groove and focused
properly on the media surface.

      A two axis flexure-type electromagnetic actuator for optical
storage applications is described in [*].  This type of actuator has
been used extensively for optical storage technology studies.  Fig. 1
illustrates this type of actuator.

      Actuator technology studies have shown that fine tracking
bandwidth requirements are generally higher than focus bandwidth
requirements.  The type of flexure actuator shown in Fig. 1 exhibits
higher bandwidth in focus than in tracking.

      This disclosure describes a design modification to this type of
actuator that matches the bandwidth characteristics of a two axis
flexure actuator to drive performance requirements for focus and
tracking.  Fig. 2 illustrates the improved actuator.

      As shown in Fig. 3, during fine tracking operation the 2 axis
voice-coil-motor (VCM) in the bobbin displaces the crossbox by
exerting a longitudinal force on the focus leaf springs, thus flexing
the fine tracking springs.

      The need to move the crossbox during tracking movement creates
a longitudinal resonance in the focus springs at about 20 Khz that
limits tracking bandwidth.  Fig. 4 is an actuator frequency response
plot that shows this limiting resonance.  Without this resonance, VCM
coil resonances beco...