分别论述了设计红外变焦距光学系统的曲线拟合法和解析法,并设计了大口径、三组元、机械补偿红外变焦距系统.系统的口径为500 mm,系统焦距为750 mm～3000 mm.从计算结果看,设计的变焦距光学系统像面稳定,成像质量良好,接近或达到了衍射极限.

Two ways, namely polynomial curve fitting method and analytic expression method, are introduced to design infrared zoom system. And an exanple of large aperture, three group elements and mechanics compensator type is given with configuration D=500 mm, f′=-750~-3000 mm. The results show that the image of the optical system approached or reached to the diffraction limit.