Design of an ultrawide angle catadioptric lens with an annularly stitched aspherical surface

We present an ultrawide angle catadioptric lens with a field of view (FOV) of 360° × 270° and F/# of 2.5. The lens consists of two optical configurations: the center configuration is all-refractive and has a FOV of ± 50° and the catadioptric configuration covers the remaining FOV. The MTF at 119lp/mm of the rear FOV (90° to 135°) can be improved by 0.15 via applying an annularly stitched aspherical surface (ASAS) to the rear surface of the catadioptric element. The developed lens presents smaller marginal distortions and higher relative illuminations compared with traditional panoramic lenses. A proof-of-concept prototype producing acceptable image quality is developed.