Fabrication of microlens arrays by a rolling process with soft polydimethylsiloxane molds

Abstract

In this paper, we present a new roll-to-roll method to fabricate visible light transparent microlens arrays on a glass substrate by using soft and cost-effective polydimethylsiloxane (PDMS) molds. First, we fabricated microlens array master molds by photoresist thermal reflow processes on silicon substrates. We then transferred the pattern to PDMS molds by a spin coater. After making the PDMS molds, we used a two-wheel roll-to-roll printing machine to replicate ultraviolet resin microlens arrays on glass substrates. The PDMS molds can be made easily at a low cost compared with traditional electroplating metal molds. We studied the quality of microlens arrays that were replicated by different rolling pressures of 20, 200 and 500 N cm−2. We also identified the relation between the pressure and the shape of the microlens arrays. The results showed that the best yield rate and replication performance were achieved with a pressure of approximately 200 N cm−2 and 4 min of ultraviolet light exposure.