Application of inclined-exposure and thick film process for high aspect-ratio micro-structures on polymer optic devices

Abstract

In this paper we apply an inclined-exposure technology, while also using a polymeric material to make 3D optical micro-structure like dove prism and hardened reflecting mirrors in blue-DVD pickup head module. In contrast to the more common type of inclined mirrors, single-lensed reflecting mirrors, the micro-reflecting mirror being developed within the scope of this paper possesses the qualities that it requires no metal for its reflecting surface, and it is structurally stable. When used in micro-optical systems, it is less prone to experiencing structural changes and impact to the system’s optical paths as a result of heat generated from the light source. The fabrication technology for dove prism being developed can be used to easily fabricate highly integrated micro-optical systems. The structure being fabricated can reach a height of 1.8 mm, while the degree of surface roughness meets the necessary Marechal optic quality criterion. In this paper we will also issue of the structure of the SU-8 material being wider at the top and narrower at the bottom due to short-wavelength light source having shallower penetration. The polymeric material used has a high penetration rate of 95% (red light), and is low in cost. As such, we may apply and consolidate micro-structures in TIR, CD/DVD, SPR, and micro-PIV systems, or optical systems in general. These novel methods can be employed for the fabrication of nontraditional 3D structures on photo polymer for Optical MEMES applications.