Glass-glass molding of concave-convex double-sided microlens arrays with high alignment accuracy

Abstract

The utilization of a double-sided microlens array (DSMLA) eliminates optical energy loss, eliminates assembly errors, simplifies the optical system's structure, and enhances overall performance efficiency. Precision glass molding (PGM) has been applied to fabricate DSMLAs, and the accuracy of aligning the molded DSMLAs significantly impacts optical performance. This study delves into the thermal deformation mechanisms of glass to present a novel approach: utilizing a metal mold core for manufacturing a high transition temperature (T_g) glass microlens array (MLA). Subsequently, this high-T_g glass MLA is combined with the metal mold core, serving as upper and lower cores, to manufacture low-T_g glass concave-convex DSMLAs. The study scrutinizes the impact of optical energy loss rate and alignment errors in concave-convex DSMLAs on optical performance. Moreover, a method to control alignment errors in concave-convex DSMLAs is proposed to boost lens alignment accuracy. A finite element simulation model was established to evaluate the forming speed and stress distribution of the concave-convex DSMLAs. Experimental findings demonstrate that high-T_g glass as a mold core facilitates high-precision shape transfer, resulting in concave-convex DSMLAs with high alignment accuracy. Optical measurements reveal that the DSMLAs exhibit excellent beam shaping effects with spot uniformity at 97.23 %. The method provides a strategy for creating concave-convex DSMLAs with high alignment accuracy.