摘要
航空遥感器在高速飞行时,由于光学窗口玻璃与大气间的摩擦会产生大量热,致使光学窗口玻璃在热载荷作用下发生变形,光束通过时会发生偏折、产生光程差等问题,导致航空遥感器的光学系统成像受到影响。为了更好地抑制这种影响,介绍了双层光学窗口的结构,并结合实例验证,对比分析了同等厚度下单、双层光学窗口的光学性能。根据窗口结构给出了在满足外界作业环境下,圆形和矩形窗口厚度的确定方法及不同窗口安装方式对厚度的影响;分析了在压力和温度的影响下,窗口玻璃的变形情况,并结合载机飞行工况对双层窗口进行了热变形分析;结合实际光学系统,验证了双层窗口的光学性能,并和同等厚度的单层窗口进行对比。分析结果表明,在航空遥感器高速飞行条件下,与同等厚度的单层窗口相比,双层窗口玻璃的径向温差和轴向温差更小;针对所研究的光学系统,双层光学窗口玻璃热变形后引起的光学系统离焦量更小,并且对光学系统调制传递函数（MTF）的影响更小,空间频率在0～65 cycle/mm范围内不低于0.3,且在65 cycle/mm时MTF的相对下降量不超过10%,即双层光学窗口的引入使光学系统在不用调焦的情况下就可以满足使用要求。对双层光学窗口的分析研究也可以为其他航空光学窗口设计提供参考。
On the operation of high-speed flight, a large amount of heat is produced due to the friction between the optical window glass and the atmosphere, by which the optical window glass deforms. Then, as light pass though the deformed window, problems as bending and difference of optical path are presented, which affect the optical system imaging of aerial remote sensor. In order to restrain the influence, the structure of the double optical window is investigated, and the optical performance of the monolayer and double optical window is analyzed. According to the window structure, methods determining the thickness of circular and rectangular window are provided on the outside working environment as well as the influence of different window installation of thickness. The deformation of optical window on the influence of pressure and temperature is analyzed, and thermal deformation analysis of the double window is also investigated combined with the flight condition. The optical property of double window is verified and compared with the equivalent thickness of the monolayer window. Analysis results show that under the condition of airborne remote sensing device speed, the radial temperature difference and axial temperature difference of double window glass are smaller than those of the monolayer window with the same thickness. For the studied optical system, the coke quantity of double optical window glass caused by hot deformation is smaller and the effect to the modulation transfer function（MTF） of optical system is weaker. The influence of the spatial frequency ranging from 0 to 65 cycle/mm is no less than 0.3 and the relative decline of MTF is no more than 10% with spatial frequency 65 cycle/mm. The optical system of the double optical window can satisfy the use requirement in the case of without focusing. The analysis study of double optical window can be referenced in the domain of designing the optical window of aerial remote sensor.
出处
《光学学报》
EI
CAS
CSCD
北大核心
2015年第1期370-378,共9页
Acta Optica Sinica
基金
国家林业公益性资助项目(201204515)
关键词
光学设计
光学窗口
双层窗口
高速航空遥感器
热光学分析
optical design
optical window
double optical window
high speed aerial remote sensor
thermal optics analysis
