复杂形面厚壁聚合物光学器件精密及超精密注塑成型方法的基础研究

复杂形面厚壁光学镜片是虚拟可视系统及激光打印机等典型光电产品的关键成像元器件，由于其厚度大及面形复杂导致体积收缩大、面形精度低且残余应力显著，成为聚合物光学器件制造的难点。本项目提出了基于面形的变模温辅助成型及模内微动校形相结合的方法来实现厚壁复杂形面聚合物光学器件的精密与超精密注塑成型。项目以厚壁棱镜和自由曲面f-theta扫描透镜为研究载体，从形面的加热／冷却分段式变模温系统及模内微动校形系统基础分析入手，重点研究基于模温的流动引发分子取向的形成及抑制机制，以及聚合物材料在粘弹态温度下的微米及亚微米面形微动补偿机理和微动压缩条件下的模内残余应力释放机制。在此基础之上，研究了聚合物光学器件面形精度及残余应力的长期演化对成像品质及涂层的影响及其工艺控制方法。本研究推动了我国在聚合物光学器件精密及超精密制造领域的发展 。

Complex form thick optical lenses are key imaging elements of opto-electronic products. Thick wall causes problem of significant volumetric shrinkage, while the complex form surfaces lead to uneven cooling. As a result, it is very much difficult to achieve high form accuracy with significant low residual stress, which challenges precision manufacturing technology. This proposal aims at developing a precision/ultra-precsion injection molding approach using a combined method of conformal variotherm mold temperature control and in-mold micro compression to produce polymeric thick complex form optical lenses. Based on thick prism and f-theta freeform scan lenses, a conformal variotherm system is developed. The mechanism of relaxation of oriented molecules during filling and packing process is characterized based on experiments and numerical simulation. The mold temperature is used to control the orientated molecular relaxation developed during filling and packing stages. Additionally, the form error compensation mechanism under micron and submicron compression is studied by numerical simulation and experiments at viscoelastic state of the material. Long-term stability of form accuracy and residual stress on imaging quality and coating is also evaluated, where a process based optimization method is proposed to obtain stable optical elements for long-term use. This project will finally promote the fundamental study and process development of precision and ultra-precision manufacturing of plastic optics.