为了对电晕放电进行全天候的检测，设计了一套包含日盲紫外、可见光和长波红外的三波段电晕检测光学系统。为了减小系统体积，提高系统性能，日盲紫外和可见光波段采用共光路结构；长波红外段采用独立光路，利用衍射面特殊的色散特性和非球面技术对系统进行单色像差和色差校正，减少系统的镜片数量。系统采用单镜片调焦设计来保证其在-40~60 ℃内清晰成像。对设计的系统进行了像质评价，结果表明，在空间频率60 lp/mm处，20 ℃时全视场内日盲紫外波段系统的MTF>0.37，可见光波段系统的MTF>0.35；在空间频率20 lp/mm处，全视场内长波红外波段系统的MTF>0.6，3个波段均能清晰成像，满足电晕检测的要求。

In order to detect corona discharge in all weather situations, a three-band optical system worked at three bands of the solar blind UV, visible and the long infrared was designed for the corona detection. To reduce the system volume and improve the performance merits, a co-lens system was used for both the solar blind UV and visible bands, and an independent lens system containing aspheric surfaces and diffraction surface was adopted for the long infrared band to correct monochromatic and chromatic aberrations. Furthermore,the focusing system was designed with a single lens to ensure an excellent imaging in the temperature from -40 ℃ to 60 ℃. The image quality of the system was evaluated,and it is shown that at the temperature of 20 ℃, the MTF at the spatial frequency of 60 lp/mm is greater than 0.37 in the solar blind UV, and greater than 0.35 in the visible band for the whole fields of view; the MTF at the spatial frequency of 20 lp/mm is greater than 0.6 in the long infrared band for the whole fields of view. These results indicate that the system has excellent imaging characteristics at all three bands, and can be used in the detection of corona discharge in all weather situations.