Free-form objective for three generation image intensifier

The GZIII.18/18-ZQ is a spherical three generation image intensifier, whose cathodic sensitivity and signal-to-noise ratio index are significantly improved compared to the second generation, which can improve the night detection capability and observation effect of the microlight night vision. According to the spectra of three generation image intensifier spectral response, sensitivity, signal-to-noise ratio and other parameters, combined with the system requirements of the field of view, resolution and other technical indicators, a low level light system is designed with a focal length of 20.00mm, F number 1.29 and the field of view of 50 degrees. The system uses four lenses, the total length of the total objective is less than 60mm, and the weight is less than 100g. Using a free-surface prism to achieve optical circuit rotation, the performance is improved. Finally, we get the off-axis MTF curve in 40lp/mm greater than 0.5, the whole field of view distortion is less than 4% without vignetting, the transmission rate is greater than 83%.