无需等高共轴调节且快速测量凸透镜焦距  

Fast measuring the focal length of convex lens without equal high coaxial adjustments

作　　者：何友武 翁存程 HE You-wu;WENG Cun-cheng(College of Photonic and Electronic Engineering,Fujian Normal University,Fuzhou 350007,China;College of Physics and Energy,Fujian Normal University,Fuzhou 350007,China)

机构地区：[1]福建师范大学光电与信息工程学院,福建福州350007 [2]福建师范大学物理与能源学院,福建福州350007

出　　处：《实验室科学》2019年第1期57-59,共3页Laboratory Science

基　　金：福建省自然科学基金(项目编号:2015J01301);福建省教育厅科技项目(项目编号:JA15128;JAT170124)

摘　　要：提出了一种基于夫朗和费衍射测量凸透镜焦距的方法。一束平行光垂直入射光栅,从光栅出射的衍射光经待测凸透镜后照射CCD。CCD沿轨道平移,同时计算机记录正负一级衍射条纹最细时CCD在轨道上的位置及条纹在CCD上的位置,然后计算机分别计算出这两个位置和这两条纹的间距,最后计算机根据夫朗和费衍射公式计算给出待测透镜的焦距。这种测量方法无需调节待测凸透镜与测量系统等高共轴,也无需测量物距、像距等,而且快速、准确、不受景深影响。In this paper, a method for measuring the focal length of convex lens is presented. This method is based on Fraunhofer diffraction. A parallel light is vertically incident to a grating. The diffracted light, escaping from the grating, passes through the convex lens and then illuminates a CCD. The CCD is moved along an optical slide-way, and a computer records the positions of the stripes on the CCD and the CCD on the optical slide-way when the positive and negative first order diffraction stripe is the finest. Then, the computer calculates the spacing of the two positions of CCD on the optical slide-way and the two stripes on the CCD, respectively. At last, according to the formula of Fraunhofer diffraction, the focal length of convex lens is obtained by the computer. This method does not need to adjust the equal high coaxial of the convex lens and the measuring system, and to measure the object and image distances. Furthermore, this method can obtain the focal length of convex lens quickly and accurately, and is not affected by the depth of field.

关 键 词：夫朗和费衍射 凸透镜 焦距 

分 类 号：O433[机械工程—光学工程]