We present a new method to manufacture arrays of microlenses with varying diameter and/or varying focal length on the same substrate material. The method combines direct laser machining with a casting method and is based on the exposure of poly-methylmethacrylate (PMMA) to an UV Excimer Laser (248 nm). A following thermal treatment of the PMMA results in spherical caps in the PMMA which subsequently serves as a mould to replicate inverse structures in poly-dimethylsiloxane (PDMS) by casting. Lenses with a focal length of 300 µm to 4,000 µm have been realized in a PDMS replicate from the PMMA, however, this method is not limited to these materials if the soft embossing technology is applied where an elastomer such as PDMS serves as the mould.
Proceedings of Spie Optics East, 2004
Main Research Area:
Lab-on-a-Chip: Platforms, Devices, and Applications, 2004
SPIE - International Society for Optical Engineering