基于变像管工作原理并从其整体性能优化的角度出发，得出在其中采用准层流电子束的必要性；通过分析已有电子光学聚焦系统所存在的结构和性能上的缺陷，确立了优化电子透镜系统的基本模型.在分析各参量相对变化对其渐进聚焦调制特性影响的基础上，阐明了通过膜孔透镜的引入而形成对电子束横向尺寸具有渐进压缩特性的准层流电子枪的可能性.

Based on the operating principle of image converter tubes,an analysis of the disadvantageous effect of the existing electron beam cross-over section on its overall performance was made.The emphasized consideration of performance optimization means that it is necessary to adopt the quasi-laminar flow electron gun.A basic analytical model of optimized system of focusing electron lens is well established through the comparative analysis on the deficiency of focusing performance of the commonly used electrostatic electron lens and magnetic one.Furthermore,by getting an insight into the dependence of focusing properties on the relative geometrical parameters and potential ones of the referred electrostatic lens system,the realizability of the novel quasi-laminar flow electron gun with excellent incrementally compressive modulation property was illustrated in terms of applicability,correctness and practicality.