同质材料反射系统热特性研究

Study on thermal characteristic of homogeneous material reflective system

为从原理上阐述同质材料反射系统的温度特性,并为光学系统设计提供依据。以热变形特征及其计算方法为基础,以光学系统焦点为研究对象,依次介绍单反射镜、共轴多反、离轴反射系统的温度特性,并建立了相应热差模型。仿真结果表明,离轴三反系统后焦距随温度的变化情况与对应镜筒的热变形量完全一致,其在较大温差范围内具有良好的成像质量。由温度变化引起的热离焦可被镜筒补偿,验证了理论模型的正确性,得出在均匀温度场条件下同质材料反射系统无热差的结论。因此,当光学系统尤其是热差效应明显的红外系统采用同质材料反射系统时具有良好的温度适应性。

In order to expound the temperature characteristics of homogeneous material reflective system in principle,and provide the basis for the design of optical system,the temperature characteristics of single mirror,coaxial multi-mirror reflective system and off-axis reflective system were introduced successively,which were based on the thermal deformation characteristics and its calculation method,and the optical system focus was taken as the research object.Meanwhile,the corresponding thermal aberration model of reflective system was established.The simulation results show that the change of focal length with temperature in the off-axis three-mirror reflective system is completely consistent with the thermal deformation amount of corresponding lens barrel,and it has good imaging quality in the range of large temperature difference.The thermal defocus caused by the temperature change can be compensated by the lens barrel,which verifies the correctness of the theoretical model and draw a conclusion that there is no thermal aberration in the homogeneous material reflective system in the condition of uniform temperature field.Therefore,the optical system,especially the infrared system with obvious thermal aberration effect has good temperature adaptability when the homogeneous material reflective system is adopted.