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Freeform optical design for a nonscanning corneal imaging system with a convexly curved image

 
: Nie, YF.; Gross, H.; Zhong, Y.; Duerr, F.

:

Applied optics 56 (2017), No.20, pp.5630-5638
ISSN: 0003-6935
ISSN: 1539-4522
ISSN: 1559-128X
English
Journal Article
Fraunhofer IOF ()

Abstract
Most existing techniques that are typically used by specialists to image the cornea are based on point, slit, or annular scanning due to a narrow field of view. The difficulty in achieving a larger field of view comes from the convex shape of the human eyeball. Field curvature for a refractive imaging system with positive power is typically negative and thus a concave image surface. In order to view the full cornea and sclera with snapshot imaging, we calculate qualified two- and three-mirror solutions from Seidel aberration theory. A three-mirror solution is further optimized as a high-resolution off-axis imaging system using freeform surfaces, which can obtain a full-field tailored image shell without scanning. The lateral resolution on the cornea is about 10 mu m with good modulation transfer function (MTF) and spot performance. To ease the assembly, a monolithic design is achieved with slightly lower resolution, leading to production solution.

: http://publica.fraunhofer.de/documents/N-480588.html