Thermal difference analysis and athermalization Design of infrared optical system

摘要

When infrared optical system works in a large temperature range, the thermal effect of optical lens and optical tube will produce image plane shift and lead to imaging quality deterioration. In order to eliminate the thermal aberration, the athermalization design principles of infrared optical system were introduced, and some commonly used methods of thermal difference compensation were described. Proceeding from single lens, the thermal difference caused by temperature changing was analyzed, and the relationship between temperature and focus shift was obtained. Considering optical tube thermal expansion, a set of equations to estimate the thermal difference of lens group was given. Finally, anrninfrared optical imaging system that can work under the temperature range of -40°C to 60°C was design according to athermal technique, in which a new mechanical passive temperature compensation was proposed. Through simulation, the athermalization design could make imaging plane shift the smallest. The simulation results coincided with the theoretical formula, and the design had reference value in engineering.