双波段共口径成像系统光机设计与分析

Opto-mechanical design and analysis of dual-band sharing aperture imaging system

为了克服机载光电有效载荷(可见光摄像机和红外热像仪)各自独立、焦距过短的缺点,着重对可见光/红外共口径系统关键技术进行了研究。采用可见光、中波红外双波段共用主次镜的光学结构,可见光和红外焦距分别为1 500 mm和750 mm。选用合适的光学材料、合理的支撑方式,对系统反射镜支撑组件进行了静力学、动力学建模,优化了结构形式。采用光机热集成分析方法,指导、评价和优化光机系统设计过程,提高结构固有频率,增强系统热稳定性适应范围。系统结构设计基频大于200 Hz,在±5℃均匀温变工况和重力作用下,反射镜面形PV值小于λ/10,RMS值小于λ/40,光学系统传递函数(MTF)达到0.38。结果表明,采用该方法设计的光机结构固有频率高,重力及热耦合变形、抗振性能等方面均能满足要求,系统具有良好的成像质量。

In order to overcome the shortcomings of the airborne photoelectric payloads （visible light cameras and infrared thermal imager）, which has too short focal length and independent with each other, the visible light/infrared sharing aperture system key technology were studied. With visible light and medium wave infrared dual band sharing the primary and secondary mirror, the optical system focal lengths were 1 500 mm and 750 mm respectively for the visible light and infrared wave. By choosing appropriate optical material and the reasonable support method, the system reflector support component＇s static and dynamic models were designed, the structure form was optimized. The thermal-structural-optical integrated analysis method was used to guide, evaluate and optimize the opto-mechanical systems design process, improve the natural frequency of the structure and enhance thermal stability range. The fundamental frequency of the structure is greater than 200 Hz, the surface precision of the system reflectorreaches PV of λ/10 and RMS of h/40. The optical system modulation transfer function （MTF） reaches 0.38 under influence of deadweight and uniform temperature change of ±5 °（2. The results indicate that the proposed design can meet the requirements of high structure natural frequency, the gravity and thermal coupling deformation, vibration resistance, etc, and the system has good imaging quality.