大入瞳距双通道红外投影系统设计

Dual-channel infrared projection system design with large entrance pupil distance

由于受光学系统结构和使用条件的限制,红外投影仿真系统要求目标/干扰发生器共用一个光学系统,入瞳距大于1000mm,光学件质量小于等于3kg,体积限制在Φ250mm×480mm范围内。在原理设计上,采用无焦系统与后聚焦镜组的复合方式,在平行光路中加入平面耦合镜,实现了在大入瞳距条件下,目标/干扰共用同一光学系统的设计。此外,系统中采用了两个非球面,保证了系统在较少的光学零件情况下具有优良的像质和要求的透过率。同时,只需沿轴移动最后一组透镜,就可以实现调焦。最终设计结果为:全系统共有11个光学零件,质量约2.5kg,入瞳距1050mm,最大口径为220mm,全视场MTF大于等于0.7,90%能量集中在20μm弥散圆内,满足了系统要求的各项技术指标。

Due to the limitations of the optical system structure and the application conditions, the target/interference generator of an infrared projection simulation system is required to share an optical system, in which entrance pupil distance is greater than 1 000 mm, the weight of its optical elements no more than 3 kg, and its volume within Ф 250 mm ×480 mm. In order to make the target/interference generator share the same optical system with a large entrance pupil distance, the combination of an afocal system and a back focal lens group were adopted, the coupling plane mirror was inserted into the collimation light path. In addition, two aspheric surfaces were used to ensure its high image quality and required transmittance with fewer optical parts. And focusing could be realized by moving the last lens group along its axis. The finally designed system, which includes eleven optical elements and weighs about 2.5 kg, satisfies the required technical qualifications so that its entrance pupil distance is 1 050 mm, its maximal aperture 220 mm, its MTF no less than 0.7, and its 90 percents of enclosed energy within the circle of 20 μm diameter.