头盔式微光夜视仪中折/衍混合物镜的设计

Design of refractive/diffractive objective lens for head-mounted night vision system

为了使头盔式微光夜视仪结构更加紧凑和小型化,在成像物镜设计中引入衍射面,利用衍射光学元件(Diffractive Optical Elements,DOE)独有的负色散性质和光波面任意相位调制的特点,运用CODEV光学设计软件,设计了焦距为25 mm,视场为40°,相对孔径为1/1.2,全视场畸变≤5%的头盔式微光夜视仪的折/衍物镜系统,并讨论了适用于加工衍射面的结构参量。结果表明在物镜光学性能保持不变的情况下,所设计的折/衍物镜与传统物镜比较,成像物镜在使用两个衍射面后,提高了物镜的成像质量,镜片数由原来的9片减少到了7片,光学总长由原来的75.9 mm缩短为57.8 mm。

To improve the imaging quality of the lens of night vision imaging system on headpiece and make lens light in weight, small in size, compact in structure, the lens was designed with diffractive surface. The Diffractive Optical Elements （DOE） have the properties of negative dispersion and random phase modulation of light wave surface. By using optical design software CODEV, we designed a refractive/diffractive system for a helmet-mounted low-light level night vision device, the parameters are：focal length：25mm; field of view： distortion of TFOV： 5 %. Compared with the traditional lens of night vision imaging systems, the designed lens imaging quality was improved, the size and weight was decreased. Finally the structure parameter of the lens with diffractive surfaces which can be used to manufacture was discussed in detail.