Browse Prior Art Database

Rotating Periscope Optical Tape Head

IP.com Disclosure Number: IPCOM000100929D
Original Publication Date: 1990-Jun-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 2 page(s) / 50K

Publishing Venue

IBM

Related People

Sincerbox, GT: AUTHOR

Abstract

Described is an optical head design that can be used with a diode laser array in an optical tape storage system to provide high data transfer rates. The concept is based on a two-mirror optical periscope wherein an image can be translated without altering its orientation.

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Rotating Periscope Optical Tape Head

       Described is an optical head design that can be used with
a diode laser array in an optical tape storage system to provide high
data transfer rates.  The concept is based on a two-mirror optical
periscope wherein an image can be translated without altering its
orientation.

      For use in a tape system, the simple optical system shown in
the figure is sufficient.  Light from the laser array and
beam-shaping optics (not shown) is introduced into one mirror of the
periscope.  Light passes to the second mirror and is focused by the
objective lens onto the recording surface of the tape.  The periscope
is rotated about an axis determined by the first mirror of the
periscope and the input beam direction.  The resultant image,
depicted as an arrow in the top view, moves in a circular path but
retains its orientation.  Light returns to the detection system (not
shown) without any image rotation, thus preserving alignment.  Focus
and tracking actuators, also not shown, are of the conventional
variety.

                            (Image Omitted)

      With this type of motion, the data tracks move closer together
with rotation angle and cross over at 90o .  The spacing of the
tracks decrease with angle according to d cos r.  Hence, an initial
spacing of 1.5 mm becomes 1.3 mm at 30o .  Assuming a variation of +
0.1 mm in track spacing can be tolerated (i.e., 1.4 + 0.1 mm), then
data can be...