凹透镜焦距测量中的景深和误差分析  

The Depth of Focus and Error Analysis of Measuring the Focal Length of Concave Lens

作　　者：黄志平[1] 陈志华[1] 冯卓宏[1] 郑卫峰[1] 

机构地区：[1]福建师范大学物理与能源学院,福建福州350007

出　　处：《实验室研究与探索》2013年第10期21-24,共4页Research and Exploration In Laboratory

基　　金：福建省教育厅基金资助项目(JA09042);福建师范大学本科教学改革研究立项项目

摘　　要：通过分析景深、位置测量的随机误差与凹透镜焦距测量值的关系建立了数学模型,并推导出相应的函数关系,总结了影响凹透镜焦距测量值的因素。通过理论分析发现,选择凸透镜的物距大于2倍的凸透镜焦距使得虚物为小像较为合适,然后选择较大的虚物物距可以减小焦距的测量误差。在仪器调节方面,给出不同操作方式中景深和位置测量误差对焦距测量值范围的影响,发现通过固定凸透镜和像屏而移动凹透镜的操作方式更容易获得清晰的再次成像,这有利于实验中提高凹透镜焦距测量的精度。In experiments,the error of focal length came into being through these ways： the co-axial adjustment, the depth of focus and the random error of position measurement. By the analysis of auxiliary approach to measure the focal length of concave lens, a mathematical model was established. By the model the function equation between the focal length with the depth of focus could be displayed, as well as the random error of position measurement. The influence factor of measured values of focal length was estimated. Through the theoretical analysis, the findings suggested that the object distance of convex lens should be more than the double of image distance of convex lens, and then it was suitable for choosing the greater object distance of virtual object to reduce the error of focal length. Besides, it indicated that the depth of focus and the random error of position measurement had different effects on the error of focal length by different instrument adjustment. Clear image was more easily obtained from experiments by fixing convex lens and screen and changing the position of concave lens.

关 键 词：凹透镜 焦距 景深 误差分析 

分 类 号：TH741[机械工程—光学工程]