摘要
采用五点差分法计算轴对称静电透镜子午面上电位分布 ,再从普遍轨迹方程求得的电子轨迹出发得到透镜焦点和球差。根据不同种类静电透镜的结构特点 ,通过改变它们电极上的电位比和电极本身及电极之间的几何尺寸算出它们的焦距和球差变化 ,最后得到由这些变化产生的对透镜性能的影响。本文具体分析了膜孔透镜 ,浸没双圆筒透镜 (包括等径和不等径 ) ,单透镜和浸没物镜这四类最主要的静电透镜。
The five points difference method is used to calculate the voltage distribution on the meridian surface of axial-symmetrical electrostatic lens. Then common track formulation is applied to get the electron tracks. The focus and spherical aberration of the lens are obtained from the tracks. The voltage ratio of the electrodes, the geometry of the electrodes and the geometry between the electrodes are changed based on the structure features of different types of lens. Then the focus and spherical aberration of the different conditions of different types of lens are obtained. These results lead to the influence on the performance of lens. This paper focuses on four main types of axial-symmetrical electrostatic lens: film aperture lens, double-cylinder immersion lens, convex lens and immersion object lens. The results are very useful to judge the direction of the lens design.
出处
《电子器件》
CAS
2004年第4期641-649,共9页
Chinese Journal of Electron Devices
关键词
轴对称静电透镜
焦距
球差
axial-symmetrical electrostatic lens
focus
spherical aberration
