Open AccessApplying slope constrained Q-type aspheres to develop higher performance lenses
Author(s) -
Bin Ma,
Lin Li,
Kevin P. Thompson,
Jannick P. Rolland
Publication year - 2011
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.19.021174
Subject(s) - optics , tilt (camera) , lens (geology) , lithography , surface (topology) , sensitivity (control systems) , numerical aperture , aperture (computer memory) , materials science , physics , computer science , mathematics , geometry , engineering , acoustics , electronic engineering , wavelength
It has recently been shown that the coefficients that specify the aspheric departure from a spherical surface in high NA lithographic lenses routinely require more significant digits than are available in even double precision computers when they are described as part of a power series in aperture-squared. The Q-type aspheric description has been introduced to solve this problem. An important by-product of this new surface description is that it allows the slope of a surface to be directly constrained during optimization. Results show that Q-type aspheric surfaces that are optimized with slope constraints are not only more testable, an original motivation, but, they can also lead to solutions that are less sensitive to assembly induced misalignments for lithographic quality lenses. Specifically, for a representative NA 0.75 lens, the sensitivity to tilt and decenter is reduced by more than 3X, resulting in significantly higher lens performance in-use.