Design of Hybrid Diffractive and Refractive Wide-Angle Objective

Wide-angle objective matched with detector can be used for measuring the field of view of sight mirror. In order to obtain the system with good image quality and lightweight, diffractive optical elements are employed for the improvement of their image quality and the reduction of the used element number and the system weight. In this paper, a wide-angle objective was designed. Its optical parameters were that focal length was 15.5mm, diameter was 6mm, full field-of-view was 30°, its wavelength range was from 486.13mm to 656.27 mm, and its total length is less than 50mm. The Petzval structure was adopted. The system designed by hybrid diffractive and refractive (HDR) method and the one by conventional multi-pieces refractive method were compared. The results show that the HDR method can improve the image quality significantly, at the same time; the weight of the system has reduced from 85.7g to 42.3g and fit for outer use.