FABRICATION OF PMMA MICROLENSES USING A MICROMACHINED SILICON MOULD

摘要

Microlens arrays are applied in several industrial fields, such as robotics, machine control, measurement systems etc. These devices can be manufactured using several techniques. Mass production employing polymers and techniques such as spin casting embossing etc. are very popular. In this paper, this kind of device was fabricated by spin casting and curing a PMMA polymer film upon a micromachined silicon mould. The silicon mould was fabricated using wet etching, after comparing favourably to dry etching. The characterization of the transmittance of the polymer showed that this material is useful for wavelengths in the 500 nm to 2500 nm range. The fabricated devices were also optically characterized and showed to split a laser beam into a practically continuous stripe with an aperture angle of approximately 60°. The intensity variation between the maximum and the minimum orders is approximately 30%, which is a good feature for most industrial applications.