非球面玻璃透鏡模造成形之模仁形狀補償與玻璃殘留應力探討

Abstract

玻璃模造技術相較於傳統研磨拋光技術具節省成本、量產、製程簡化等優勢，但仍有困難需克服，包括模仁壽命、玻璃成品與原設計的形狀有所偏差、玻璃內部的殘留應力等。 而影響玻璃透鏡成像品質的原因主要為模造後形狀的偏差以及透鏡內部的殘留應力，因此本研究利用有限元素分析就已知詳盡材料性質的 L-BAL42 玻璃，加入熱傳的效應提升此有限元素模型的精度，並透過實驗結果的玻璃形狀驗證此模型，之後利用此模型進行模仁形狀的補償使成形後之玻璃透鏡符合原設計的形狀。另一方面，透過模擬與光彈實驗觀察玻璃的殘留應力分佈並相互驗證，最後利用最佳化方法求出增進製程效率的製程參數。

Compared to traditional grinding and polishing technique, glass molding process have many advantages in producing optical elements, such as cost savings, mass production, process simplification and so on, but there are still some difficulties must be overcame including mold life, shape deviation between the formed lens and the original design and residual stress inside the molded lens. The shape deviation and the internal residual stress are significant factor affect the image quality. Therefore, this research adapt finite element analysis with detailed L-BAL42 glass properties and thermal conductivity to improve the accuracy of the finite element model. Afterward, this model is verified with the glass shapes from experimental results. Then, the mold shapes are compensated to produce molded glass lenes with shape meet the requirement of original design. On the other hand, simulated residual stress distribution is compared with the results observed by photoelastic experiment, and optimization analysis is used to get the optimized parameter for glass molding process to enhance the process efficiency.