用傅里叶频谱测量焦距的调整误差分析

研究了用傅里叶频谱法测量球面和柱面光学系统焦距时,调整误差对测量结果的影响问题。分析结果表明,当:(1)准直物镜离焦达2.9%,即出射光束会聚度为0.2m~(-1);(2)狭缝有10mm离焦;(3)测量显微镜调焦误差为10mm时,以焦距为500mm的被测透镜为例,这些误差所产生的附加强度约为10~(-4)数量级,所以对测量结果没有显著影响。从而肯定了这种焦距测量方法具有仪器装置简单、测量精度高、调整方便、适用范围较广的优点。

THE ADJUSTING ERROR ANALYSIS OF THE FOCAL LENGTH MEASUREMENT USING FOURIER SPECTRUM

This paper has analysed the effect of the adjusting error on the meas- urement of the focal length of spherical and aspherical system.It shows that when(1)the collimator has the defocus of 2.9%,i.e the convergent degree of the exit beam is up to 0.2m~(-1),(2)the slit has the defocus of 10mm,and(3)the measuring microscope has the focusing error up to 10mm, to take a lens which is 500mm focal length as an example,the additional light strength produced by those errors is about the magnitude of 10~(-4), and has no evident effect on the measurement result,so it again proves that this focal length measurement method has the advantages of simple apparatus,high measurement accuracy,wide application and convenient adjustment.