基于扩散光束尺度的凸透镜焦距测量

Measuring the convex lens foci based on spread beam scale

采用虚拟点光源虚像法测量了透镜焦距,该方法可以规避传统焦距测量中需要对像平面的位置进行精准判定的难题.利用短焦透镜和激光器模拟点光源,使发出的光线穿过待测透镜及另一侧的光阑照在光屏上,形成光斑,通过CCD映象技术测量光斑直径及光阑到光斑的距离,从而得到透镜焦距.

The virtual image method with virtual point light source was presented to measure the foci of convex lens based on the formation principle of virtual point light resource. By using this meth- od, the difficulty of precisely predicating the accurate position of image plane in the focal length meas- urement could be avoided. Specifically, take advantage of the short focal lens and laser to simulate the point light source, the light passed through the lens could be focused into a spot on the screen at the other side of the diaphragm. The focal length of the lens was obtained by measuring the spot diameter and the distance between the diaphragm and the light spot based on CCD imaging technology.