针对激光近炸引信发射光束发散角大和远距离目标回波信号微弱等问题，通过分析大视场激光近炸引信光学结构特点，结合激光近炸引信定距影响因素，应用Zemax软件，根据非球面光学设计理论，设计出激光发射系统多级非球面准直透镜。仿真结果显示，相对于传统单级非球面准直透镜，利用多级透镜可将中心辐照亮度提高近10倍，光斑尺寸得以减小，能量集中。最后，根据设计加工非球面透镜并进行实验，结果表明该准直系统可有效压缩发射激光束光斑尺寸，提高系统探测距离。

The problems of the large beam divergence angle and short detection range in the launch system of laser proximity fuze are investigated. By analyzing the optical structural characteristics of large field laser proximity fuze, combined with characteristics of distance influencing factors, and according to aspheric optical design theory, multilevel aspheric collimating lens are designed using Zemax software. Simulation results show that, comparing with single aspheric collimating lens, multilevel lens increase the brightness of the center of irradiation nearly 10-fold, and the spot size decreases and energy concentrates. At last, aspheric lens is processed and experiment has been done, the results show that this collimating system can compress spot size effectively, and the system detection range is improved.