用等效应力法分析温度变化对胶粘反射镜面形的影响

Using the Equivalent Stress to Analyze the Effect of Temperature Change on Surface Accuracy of the Bonded Mirror

基于等效应力法分析了温度变化对反射镜面形准确度的影响.对反射镜粘接处施加一定量的径向强迫位移约束,使其受到与热应力大小一致的应力作用,在该强迫位移约束下反射镜面形变化与热应力作用下反射镜面形变化基本一致.对直径为70mm、厚度为15mm的反射镜进行粘接实验,用ZYGO干涉仪测定温变前后反射镜的面形变化.当温度由20℃降到16℃时,反射镜面形峰谷值和均方根值的变化量分别为0.005λ和0.002λ(λ=632.8nm),理论计算的峰谷值和均方根值变化量分别为0.004λ和0.002λ;当温度由20℃升高到30℃时,反射镜面形峰谷值和均方根值变化量分别为0.013λ和0.006λ,理论计算的峰谷值和均方根值变化量分别为0.012λ和0.004λ,实验值和模拟分析值基本一致.

The equivalent stress method was proposed to analyze the surface change of the mirror under the temperature change.The forced displacement restrain was applied on the bonded position of the mirror to ensure the mirror suffer the equivalent stress compared with the heat stress.The surface change of the mirror under the action of the forced displacement was consistent to the one under the action of the temperature change.A bonded experiment to the mirror whose diameter is 70 mm and thickness is 15 mm and surface accuracy of the mirror is measured by the fine ZYGO interferometer in different temperatures.It is indicated that when the temperature descended from 20℃ to 16℃,the mirror surface change of the Peak to Valley（PV）and Root Mean Square（RMS）are 0.005λand 0.002λ,while the simulation change of the PV and RMS are 0.004λand 0.002λ.When the temperature increased from 20℃to 30℃,the mirror surface change of the PV and RMS are 0.013λand 0.006λ.The simulation change of the PV and RMS are 0.012λand 0.004λ.The experimental result agrees with the simulation basically,which illustrate the equivalent stress method based on the forced displacement restrain can express the effect of the temperature change on the surface accuracy change of the mirror perfectly.