为了避免环境温度变化影响红外双波段目标模拟器的投影图像质量,对其变焦投影镜头进行了光机热分析。建立了变焦投影镜头的有限元分析模型,通过对非定常的热应力问题进行准静态处理,完成了有限元模型的热分析和静力学分析,并求解出整机随温度变化的位移云图。通过有限元数据转换算法将离散节点的坐标数据转化为矢高变形数据,利用Householder算法完成了基于Zernike多项式的镜面热变形拟合,并将拟合系数导入光学设计软件,得到了不同温度下变焦投影镜头的热分析结果。结果表明,当温度在10~30 ℃区间时,投影图像质量对整机的热变形不敏感。

In order to avoid the influence of the ambient temperature change on the projection image quality of the infrared dual-band target simulator, the integrated optical-structural-thermal analysis of the zoom projection lens of this simulator is conducted. The finite element analysis model of the zoom projection lens is established. By the quasi-static treatment to the unsteady thermal stress, the thermal analysis and the statics analysis are finished. The displacement nephogram of overall unit versus temperature is also obtained. The discrete node coordinate data are converted into the vector deformation data by the finite element data conversion algorithm. The surface thermal deformation of each lens is fitted by the Householder algorithm based on the Zernike polynomials. If the fitting coefficients are imported to the optical design software, the thermal analysis results of the zoom projection lens under different temperatures can be obtained. The results show that the projection image quality is insensitive to the thermal deformation of the overall unit when the temperature is in the range of 10-30 ℃.