Optical Design for Dual Spectral Panoramic Imaging System Applied in Corona Detector

In order to achieve the wide angle,large relative aperture and uniform illumination of corona detectors,a novel catadioptric omnidirectional optical system applied in the corona detector is presented which operates in the region of Solar Blind UV/visible.Operating principle of the dual spectral panoramic corona detector is introduced.And,the structure of the dual spectral panoramic imaging system is determined by assigning optical parameters of the primary(panoramic shell)and secondary(relay optics)groups.After investigating the origin and characters of the aberrations in the panoramic imaging system,methods for balancing aberration between the two groups and improving illumination uniformity are proposed.Finally,dual spectral panoramic imaging systems satisfying specifications are obtained.The field of view of the system achieves 360°×(45°~90°)and relative aperture extends to 1:2,the diameter of 80% encicled energy of SBUV panoramic imaging system is 20μm,smaller than the pixel size of ICCD,the MTF value of visible panoramic imaging system is higher than 0.5@83lp/mm over all fields,and the illumination uniformity on the images of SBUV /visible detectors is superior to 99.8%.The present results show that application of panoramic annular lens to the corona detector can satisfy the design requirements.