Design of large-aperture and wide-spectrum zoom lens

In the process of high-voltage power line transportation, the corona discharge is easy to occur, which has potential safety hazards. Therefore, it is necessary to detect the corona discharge. Corona detection using solar blind ultraviolet (UV) lens is one of the detection methods. Based on the multiple configuration function of Zemax, a large-aperture and wide-spectrum zoom lens was designed to cooperate with the application of UV lens with the zoom range of 90 mm~165 mm, which could quickly and accurately find out the position of the damaged line in all-weather conditions when detecting the corona discharge signal. The four components and near-symmetrical structure were adopted by the proposed large-aperture and wide-spectrum zoom lens with the F number of 1.4, the zoom range of 30 mm~55 mm, the working spectral band of 400 nm~850 nm, the full field MTF≥0.4 at spatial frequency of 100 lp/mm, and the maximum distortion≤±3 %, all adopting standard spherical design, total length of the system is 110 mm, which is suitable for 0.847 cm (1/3 inch) CCD, and can better correct all kinds of aberrations as well as meet the basic processing requirements of each part.