Athermalisation Design and Analysis of the Opto-mechanical Structure Based on Laser Radar Launching System

摘要

The paper adopts the passive mechanical athermalization method to ensure the laser radar optical launching system works steadily and continuously in the temperature range of -10°C to 50°C. Firstly, the weight ratio of the impact of temperature variations on the optical launching beam-expansion lens group is analyzed to carry out the athermalization design for the front multi-lens group. Next, the ZTC4 that matches the linear expansion coefficient of lens materials is selected based on analyzing and comparing the attributes of the lens barrel. Afterward, the redesigned elastic space ring is adopted to keep the spatial distance between each lens. Meanwhile, the distance is optimized and analyzed to construct the equation set for the size and axial direction of the elastic space ring and the stress variation. The equation set is later applied to making the rational design for the elastic space ring that achieves spatial localization. Meanwhile, optimal design parameters are selected for the elastic space ring to reduce contact stress and ensure axial consistency of the optomechanical system. Lastly, the flexible structural clamping ring is used for fastening. According to analytical results, the maximum axial displacement of the system is less than 0.06mm when the temperature of system changes; the surface accuracy of each lens is less than λ/8; the maximum stress of each lens is smaller than the yield strength of BK7 and SF8 glass lens material. All parameters meet the requirements on the athermalization design.