线扫描激光雷达光路的光机热集成优化设计

Optimization design of structural-thermal-optical integration for linear scanning laser radar optical path

发射透镜直接准直半导体激光光源方案能够使线扫描激光雷达结构更紧凑、成本更低,但是由于高功率半导体激光光源发热严重会导致光学元件热变形,从而导致探测器接收到的光功率急剧降低而不可探测。提出了一种30m探测距离的线扫描激光雷达光路的光机热集成优化设计方法。以预设工作温度40℃至80℃的中间温度60℃为初始条件,基于Zemax软件优化设计了发射透镜与接收透镜的光路系统,使工作温度为60℃时的光路系统光学性能最佳;使用有限元方法分析该光路与相应的机械结构随温度变化时光学元件热形变的情况,通过添加SiO2气凝胶作为隔热材料进行光路系统的机械结构优化。优化结果表明,采用光机热集成优化设计方法后,优化后的光路与机械结构在工作温度40℃至80℃范围内探测器接收到的光功率始终在10^-4w量级,相比仅仅使用Zemax软件优化设计发射透镜与接收透镜方法(探测器接收到的光功率10^-6~10^-4w)有了显著的提升。

The scheme of emitting lens direct collimating semiconductor laser source can make the linear scanning lidar more compact and cheaper, but the high power semiconductor laser source heating seriously will lead to the thermal deformation of optical elements, which will lead to the sharp reduction of the optical power received by the detector and make it undetectable. A thermal integration optimization design method for the optical path of line-scanning laser radar with a detection range of 30 meters is proposed. This method firstly takes the preset working temperature from 40~80℃ as the initial condition, and optimizes the optical path system of the transmitting lens and receiving lens based on Zemax software, so that the optical performance of the optical path system operating at 60℃ is the best. Secondly, the finite element method was used to analyze the thermal deformation of optical elements when the optical path and the corresponding mechanical structure changed with temperature, and the mechanical structure of the optical path system was optimized by adding SiO2 aerogel as thermal insulation material. Machine heat integration optimization results show that the optimization design method, the optimized optical path and mechanical structure in the working temperature of 40~80℃ range detector receives the light power in 10^-4w level all the time, compared with only using Zemax software optimization design method of emission and receiving lens(detector receives the light power 10^-6~ 10^-4w) has significant improvement.