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Proceedings Paper

Modeling air inclusions in high-performance objective lenses
Author(s): Zsolt Nagy; Pal Koppa; Gyorgy Nadudvari; Eric Dirix; Peter Richter
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Paper Abstract

Performances of high quality imaging systems are often affected by surface or glass defects, like scratches, bubbles or other localized disturbances. The goal of the present investigation is the modeling of air inclusions in the lens material and analyzing the resulting changes in the wavefront distortion and in the diffraction spot quality. CD and DVD focusing objectives are especially sensitive to this type of defect, since the size of the diffraction spot and the power-density distribution determines the quality of both the written pits and received signal. We used OSLO and ZEMAX optical design software to model these errors. This model includes the DVD objective lens and the disc. The objective lens is a plano-convex lens made of glass with an aspheric layer on its convex side. Bubbles are incorporated as ball-shaped air inclusions. The computations are based on ray tracing and physical optics propagation methods. From these computations we can calculate the intensity distribution in the focal spot and the encircled energy in the Airy disk. These calculations help us determine the tolerances of DVD objective lenses to air inclusions in function of the bubble size, shape and position. The practical application of the model will allow us to redefine the quality criteria for the used DVD lenses.

Paper Details

Date Published: 18 February 2004
PDF: 7 pages
Proc. SPIE 5249, Optical Design and Engineering, (18 February 2004); doi: 10.1117/12.513317
Show Author Affiliations
Zsolt Nagy, Budapest Univ. of Technology and Economics (Hungary)
Pal Koppa, Budapest Univ. of Technology and Economics (Hungary)
Gyorgy Nadudvari, Philips Components Ltd. (Hungary)
Eric Dirix, Philips Components Ltd. (Hungary)
Peter Richter, Budapest Univ. of Technology and Economics (Hungary)

Published in SPIE Proceedings Vol. 5249:
Optical Design and Engineering
Laurent Mazuray; Philip J. Rogers; Rolf Wartmann, Editor(s)

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