Shape-controlled microlens arrays fabricated by diffuser lithography

In this study, we used diffuser lithography to fabricate microlens arrays with the height smaller or larger than the radius of curvature of microlenses. The experimental results showed that the fill factor of the duplicated microlens arrays can be adjusted not only by the gap distance of clear holes on the photomask but also by the UV exposure dose. The surface morphology of the duplicated microlenses can also be altered by the exposure dose, the gap distance, and the thickness of the photomask. For example, a spherical microlens array having a fill factor very near 100% could be fabricated by using a 10-mu m gap distance and an exposure dose of 300 mJ/cm(2). Crown Copyright (C) 2009 Published by Elsevier B.V. All rights reserved.