注塑成型光学制品折射率分层模拟与实验研究

与玻璃制造光学制品相比，高分子注塑光学制品具有质量轻、易加工、抗冲击性好等优点，在航空航天、精密透镜等高端领域得到广泛应用。然而受注塑过程复杂压力场、温度场的耦合作用，注塑透明制品折射率通常呈非均匀的分布，存在角偏差、光畸变等光学缺陷。因此，开展注塑工艺对其折射行为影响的模拟与实验研究，对实现折射率可控光学制品的成型具有重要意义。基于Hele Shaw注塑理论和Lorentz Lorenz物理光学理论，构建了注塑光学制品厚度方向折射行为分层预测模型，开发了相关模拟程序，基于自主研发的注塑模软件Z-Mold实现了注塑过程与折射率分布的一体化模拟。以聚碳酸酯注塑平板件为例，利用Brewster法对折射率模拟结果进行了验证。该方法成功应用到神舟系列航天舱外服面窗的研制。

Layered simulation in thickness direction and experimental study on refractive index of injection molded optical products

Compared with glass-made optical products, polymer injection optical products have the advantages of light weight, easy processing, good impact resistance, and are widely used in high-end fields such as aerospace and precision lenses. However, due to the coupling effect of complex thermal fields and pressure fields in the forming process, injection molded transparent products usually have optical defects such as uneven refractive index distribution, angular deviation, optical distortion and so on. Therefore, the simulation and experimental investigation on the effect of injection molding process on the refractive behavior is of great guiding significance for the manufacture of transparent products with controllable refractive index. In this paper, the layered computational model for the refractive behavior in thickness direction of injection molded optical products was built based on the Hele Shaw injection molding theory and Lorentz Lorenz equation characterizing density and refractive index. The corresponding simulation program with VC++ was developed, and then was merged into the software system Z-Mold, a self-developed injection mould simulation software. Furthermore, the coupling analysis of injection molding filling, packing, cooling and refractive index distribution was successfully implemented based on Z-Mold. Taking the polycarbonate transparent square plate as an example, its refractive index distribution in thickness and flow direction was predicted and analyzed. According to Brewster's law, the refractive index values of square plate at different position were measured. The simulation results were in good agreement with the measured data, which proved that the prediction model for refractive index had high accuracy. This method had been successfully applied to the analysis of the "Shenzhou" extravehicular spacesuits mask.