Extremely wide-angle lens with transmissive and catadioptric integration

Wide-angle lenses can be generally classified into two structures: a transmitted fish-eye structure and a catadioptric structure with a panoramic annular lens (PAL). Compared with the former, the latter exhibits better imaging capability for a super-large field of view. However, the PAL causes this type of optical system to lose its imaging ability in a small field of view in front of the lens. In this study, a novel extremely wide-angle lens is designed by combining the fish-eye and catadioptric structures. The designed lens integrates the transmissive and catadioptric structures and can simultaneously observe two fields of view. The two fields of view of the lens complement each other and completely eliminate the central observation blind area of ordinary catadioptric wide-angle lens. The forward field of view of the lens is 360°×(0°-56°), and the annular field of view is 360°×(55°-115°). The total field of view of the optical system reaches 230° when only spherical lenses are used for all the optical elements. The optical model shows that the imaging quality of the extremely wide-angle lens is good, which proves the advantages of the new optical system in a large field of view.