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Optical Engineering

Effect of edge rounding and sloping of sidewalls on the readout signal of the information pits on optical disks
Author(s): Yajun Li; Hungte Lee; Emil Wolf
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Paper Abstract

The height profile of information pits (or bumps) on the data surface of an optical disk is assumed in most publications to be either rectangular or trapezoidal. Currently, when bumps or pits on an optical disk are produced by using a photoresist technique, their height profile is inevitably "rounded." Moreover, in plastics molding practice, edge rounding and sloping sidewalls of pits are advantageous factors to avoid the sharp edge becoming damaged when the replica is removed from the mold. A new expression for the height profile of pits is obtained that provides a convenient description of the geometry of the pits with different degrees of edge rounding and sloping of sidewalls. We find that λ/4-deep pits are optimum for the readout signal only when the pits have rectangular profile and are illuminated by a focused uniform beam. The optimum pit depth increases to an even greater value when edge rounding and sloping of sidewalls are taken into account.

Paper Details

Date Published: 1 September 2003
PDF: 14 pages
Opt. Eng. 42(9) doi: 10.1117/1.1596938
Published in: Optical Engineering Volume 42, Issue 9
Show Author Affiliations
Yajun Li, Symbol Technologies, Inc. (United States)
Hungte Lee, MaxEmil Photonics Corp. (Taiwan)
Emil Wolf, CREOL/Univ. of Central Florida (United States)


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