Design of athermalized infrared optical system with high-speed switching and compact dual-FOV

In this paper,a refractive optical system with secondary image is adopted to realize 1. 67 F number and 4. 6 zoom ratio,and the ratio between the total length and focal length is 1,and the zooming lens group is driven by solenoid pilot actuated valve switching structure to complete zooming in 60 ms. In addition,an optical passive compensation method is used to realize an athermalized design in the range of- 40 ~ + 50 ℃ by choosing proper optical and structural materials. The design results show that the optical system's modulation transfer function in each field is close to the diffraction limit at different temperatures under the characteristic frequency of 20 lp /mm and the system size is compact with fast FOV switching. Finally,it is proved that this dual-FOV infrared optical system can meet the requirements for application.