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Browse Prior Art Database

Flexural Pivot

IP.com Disclosure Number: IPCOM000110735D
Original Publication Date: 1992-Dec-01
Included in the Prior Art Database: 2005-Mar-25
Document File: 1 page(s) / 41K

Publishing Venue

IBM

Related People

Imaino, W: AUTHOR

Abstract

A common method for high bandwidth fine tracking actuation in optical storage drives is a rotating prism, that changes the angle of the laser beam incident on the objective lens. The reflecting prism, which may have the form of a cube with a totally reflecting internal surface, has very high mechanical resonances, which permit very high bandwidth operation. While standard rotating pin in hole pivots provide the required function, long term use may be unacceptable due to debris generation.

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Flexural Pivot

      A common method for high bandwidth fine tracking actuation in
optical storage drives is a rotating prism, that changes the angle of
the laser beam incident on the objective lens.  The reflecting prism,
which may have the form of a cube with a totally reflecting internal
surface, has very high mechanical resonances, which permit very high
bandwidth operation.  While standard rotating pin in hole pivots
provide the required function, long term use may be unacceptable due
to debris generation.

      A means for supporting the tilting prism, that effectively
constrains 5 degrees of freedom, and simultaneously provides the
required maximum static tilt while still inhibiting resonances from
participating in the transfer function is described.  Fig. 1 shows a
sketch of the flexural pivot; wires are connected to the tilting
prism at only the attachment points illustrated.  The center post is
attached to the supporting plate only.  Steel wires are used to
constrain motion while still permitting the 2 degrees of tilt
required from fine tracking.  The low mass of the wires as compared
to the mass of the tilting prism inhibits resonances of the wires
from participating in the transfer function.

      Disclosed anonymously.