Temperature adaptability design and experiment of optical windows for image quality detection

In order to realize the image quality detection and evaluation of photoelectric imaging system under the condition of temperature change, an optical window with temperature adaptation function was designed. Firstly, the influence of temperature on the surface shape of optical glass was analyzed. Secondly, the temperature adaptability opto-mechanical structure of optical window was designed. Finally, the effect of temperature change on the surface shape of optical window was analyzed by means of finite element analysis and experiment, and the validity of temperature adaptability design was verified. The experimental results show that the peak-valley (PV) and root-mean-square (RMS) values of the wave aberration of optical window are 82.90 nm and 6.96 nm respectively at room temperature of 20 ℃, the PV and RMS values of the wave aberration are 136.68 nm and 14.55 nm respectively at high temperature of 50 ℃, and the PV and RMS values of the wave aberration are 183.51 nm and 28.48 nm respectively at low temperature of −40 ℃. Under high and low temperature conditions and compared with the room temperature condition, the numerical variation trend of wave aberration is in good agreement with the finite element analysis results. Under three temperature conditions, the PV values of the wave aberration of optical window are less than or close to (1/4)λ, and the change of the surface shape of optical window caused by the temperature change is very small. The designed optical window has better temperature adaptability.