为了得到一个合理的He-Ne激光光束聚焦物镜，采用以正前凸型为基础的高折射率双片结构，应用Zemax软件进行优化设计，获得了弥散斑直径为0.002mm的He-Ne激光聚焦物镜，该镜头只需校正轴上点球差。实验结果表明：设计的镜头比低折射率单片透镜得到的弥散圆直径更小，达到0.0019mm，球差被控制在-0.05mm～+0.05mm范围内，MTF曲线所围面积变大，中心点亮度增高，符合实际需要。

In order to obtain a reasonable He-Ne laser beam focusing lens, the high refractive index double pieces with front convex is used and Zemax is adopted for optimization and design. A He-Ne laser beam focusing lens with dispersion speckle diameter of 0.002mm was obtained. Spherical aberration of the axial point was modified. The diameter of the dispersion speckle of the lens is smaller than that of single piece, which is 0.0019mm. The spherical aberration is modified to -0.05mm～+0.05mm. The area compassed by MTF curves increases. So the brightness of the center is increased, which meets practical needs.