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Proceedings Paper

Direct design of two freeform optical surfaces for wide field of view line imaging applications
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Paper Abstract

In this paper, we propose a multi-fields direct design method aiming to calculate two freeform surfaces with an entrance pupil incorporated for wide field of view on-axis line imaging applications. Both infinite and finite conjugate objectives can be designed with this approach. Since a wide angle imaging system requires more than few discrete perfect imaging points, the multi-fields design approach is based on partial coupling of multiple fields, which guarantees a much more balanced imaging performance over the full field of view. The optical path lengths (OPLs) and image points of numerous off-axis fields are calculated during the procedure, thus very few initial parameters are needed. The procedure to calculate such a freeform lens is explained in detail. We have designed an exemplary monochromatic single lens to demonstrate the functionality of the design method. A rotationally symmetric counterpart following the same specifications is compared in terms of RMS spot radius to demonstrate the clear benefit that freeform lens brings to on-axis line imaging systems. In addition, a practical achromatic wide angle objective is designed by combining our multi-fields design method with classic optical design strategies, serving as a very good starting point for further optimization in a commercial optical design program. The results from the perspective of aberrations plots and MTF values show a very good and well balanced performance over the full field of view.

Paper Details

Date Published: 27 April 2016
PDF: 10 pages
Proc. SPIE 9889, Optical Modelling and Design IV, 98890Z (27 April 2016); doi: 10.1117/12.2225439
Show Author Affiliations
Yunfeng Nie, Vrije Univ. Brussel (Belgium)
Hugo Thienpont, Vrije Univ. Brussel (Belgium)
Fabian Duerr, Vrije Univ. Brussel (Belgium)

Published in SPIE Proceedings Vol. 9889:
Optical Modelling and Design IV
Frank Wyrowski; John T. Sheridan; Youri Meuret, Editor(s)

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