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

Yunfeng Nie; Hugo Thienpont; Fabian Duerr

doi:10.1117/12.2225439

Translator Disclaimer

27 April 2016 Direct design of two freeform optical surfaces for wide field of view line imaging applications

Yunfeng Nie, Hugo Thienpont, Fabian Duerr

Author Affiliations +

Proceedings Volume 9889, Optical Modelling and Design IV; 98890Z (2016) https://doi.org/10.1117/12.2225439
Event: SPIE Photonics Europe, 2016, Brussels, Belgium

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.

Citation Download Citation

Yunfeng Nie, Hugo Thienpont, and Fabian Duerr "Direct design of two freeform optical surfaces for wide field of view line imaging applications", Proc. SPIE 9889, Optical Modelling and Design IV, 98890Z (27 April 2016); https://doi.org/10.1117/12.2225439

ACCESS THE FULL ARTICLE