Direct photofabrication of focal-length-controlled microlens array using photoinduced migration mechanisms of photosensitive sol-gel hybrid materials.

Photosensitive sol-gel hybrid (SGH) materials exhibited the peculiar photoinduced migration behavior of unreacted molecules from unexposed areas to exposed areas by selective UV exposure. Using the photoinduced migration mechanism of the photosensitive SGH materials, the microlens array (MLA) with a smooth surface was directly photofabricated, and the focal length was controlled by changing the photoinduced migration parameters. The higher photoactive monomer content and the thicker film creating a higher curvature produced a smaller focal length of the MLA. Thus, a simple fabrication and easy control of the focal length can be applicable to a fabrication of an efficient MLA.