Experimental and simulated analysis of glass deformation and filling modes during partial-filling hot embossing process

In the partial-filling hot embossing process (PFHE), the stress distribution and geometry of a glass micro-lens influence its optical performance. The deformation behavior of glass is very complex during PFHE. In order to investigate the final shape and stress distribution of glass micro-lens during PFHE, both simulations and experiments were conducted. The experiment results revealed that different glass squeeze flow conditions gave rise to various cavity filling modes, including single peak, dual peak, and sag. The simulations were conducted to analyze the deformation and filling modes of glass under various mold geometries and processing conditions by using Abaqus. The results showed that variations in the mold geometry and process parameters during PFHE led to different flow driving mechanisms. The flow behaviors of the glass, which is a highly viscoelastic state above the transition temperature, have been proved to influence the profile of micro-lens. Especially, the single peak micro-lens showed a lower surface roughness than the other two filling modes. This work provided a better understanding for the relationship between design and fabrication of glass micro-lens during PFHE.