Comparison of two panoramic front unit arrangements in design of a super wide angle panoramic annular lens.

In this paper, a new panoramic annular lens (PAL) with a super wide angle of (30°-120°)×360° is introduced that consists of two parts: a panoramic front unit (PFU) and a relay lens. First, two PFU arrangements referring to the block structured panoramic front unit (BSPFU) and the shell structured panoramic front unit are compared and analyzed in terms of their field curvature correction ability and structural feasibility for obtaining a wide angle PAL. From the comparison, the BSPFU arrangement turns out to be more promising for its good field curvature correction, structure compactness, and convenience for manufacture and assembly. Second, a relay lens composed of six lenses with three Q_bfs aspheres has been designed to match the BSPFU. Finally, image performance analysis of the optimized super wide angle PAL is presented. The results show that the designed PAL equipped with a BSPFU and a Q_bfs aspherized relay lens achieves good performance under a super wide field of view of (30°-120°)×360°.