Conventional refractive or reflection-refractive objectives for Night Vision Goggle (NVG) are more complicated because they require larger relative aperture and better correction of aberrations in broadband spectral response. However, further improvement of this objective is limited by conventional optics. Diffractive optics has some unique features, which can improve the imaging quality of the conventional optics system. First, effective dispersion of diffractive optics is opposite in sign to that of refractive elements, the monochromatic aberrations are easier to be corrected. Second, diffractive optics does not contribute Petzval field curvature. Third, another advantages of diffractive optics applied to the objective design are to reduce number of optical elements, overall weight and system cost. Finally, optical imaging quality of NVG that compares with the conventional optics is improved significantly. The paper will describe two hybrid diffractive-refractive objective design configurations of NVG and show comparable or improved imaging quality compared with conventional six-element objective.
展开▼
