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旋转对称电子光学系统由于加工、装配公差引起的中心偏是限制图象质量进一步提高的重要因素。过去的研究工作都仅限于对中心偏进行理论上的分析或实验上的测量,没有将中心偏和图象质量联系起来。本文在评述了已经研究的工作基础上,首次采用有限差分法计算了三维场来分析电子透镜的中心偏问题。给出了等径双圆筒透镜的中心偏对图象质量的影响。最后还做了实验,结果表明理论计算与实验结果相一致。
Rotationally symmetric electronic optical system due to processing, assembly tolerances caused by the center is to further improve the image quality is an important factor. In the past, the research work was limited to the theoretical analysis or experimental measurement of the center, without linking the center to the image quality. Based on the work that has already been done, this paper firstly analyzes the problem of the center of the electron lens by using the finite difference method to calculate the three-dimensional field. The influence of center deviation of equal diameter double cylinder lens on image quality is given. Finally, the experiment was done, the results show that the theoretical calculation and experimental results are consistent.