温差条件下组合色散棱镜支撑结构的实验分析

Experimental analysis of support structure for combined dispersing prisms at temperature difference

介绍了超光谱成像仪采用的组合色散棱镜的支撑结构形式,讨论了温度变化对成像的影响。根据使用需求选择了支撑座的材料,模拟了5～10℃温差条件下棱镜组件的变形情况。利用有限元法解决材料线膨胀系数不同所引起的棱镜反射面变形,并分析了采用聚四氟乙烯垫片做温度补偿后垫片的厚度及接触面积对石英棱镜面型的影响。实验结果表明,在支撑座和棱镜之间增加聚四氟乙烯垫片后,石英棱镜的面型达到了λ/6的指标要求。本文提出的优化方法为组合色散棱镜支撑结构的设计提供了参考依据。

The support structure of the combined dispersing prisms used in a hyper-spectrum imager is introduced, and the influence of the temperature changing on the image quality is discussed. The material of the clamping support is chosen according to the requirments, and the deformation of prism assemblies is simulated with the Finite Element Method（FEM） at the temperature differences of 5 ℃ to 10 ℃. It resolves emphatically the deformation of a prism reflector caused by the different linear expansion coefficients and analyzes the effect of the thicknesses and contact areas of the gaskets on the surface profiles of prism assembiles after the PTEE gaskets are used as a temperature compensation. Experimental results show that the surface profile of the quartz prism meets the requirement of λ/6 when the gaskets are added between the clamping support and the prism. The optimal result provides a reference for the support structure design of the combined dispersing prism.