A reflow process for glass microlens array fabrication by use of precision compression molding

A novel low-cost, high-volume fabrication method for glass microlens arrays was developed by combining compression molding and thermal reflow processes. This fabrication process includes three major steps - i.e., fabrication of glassy carbon molds with arrays of micro size holes, glass compression molding to create micro cylinders on a glass substrate, and reheating to form microlens arrays. As compared to traditional polymer microlens arrays, glass microlens arrays are more reliable and therefore may be used in more critical applications. In this research, microlens arrays with different surface geometries were successfully fabricated on a P-SK57 (T-g=493 degrees C) glass substrate using a combination of the compression molding and thermal reflow processes. The major parameters that influence the final lens shape, including reheating temperature and holding time, were studied to establish a suitable fabrication process. A numerical simulation method was developed to evaluate the fabrication process. Finally, both surface geometry and optical performance of the fabricated glass microlens arrays were analyzed.