Photo-sculpting technology for the fabrication of complex surfaces for micro-optic and micro-engineering applications

Summary form only given. The authors describe a generic technology which can enable the fabrication of surface relief structures of great complexity. The initial work was aimed at providing micro-optic lens plates for improving the performance of infrared detectors. For improved optical efficiency, the need arose for high fill factor lens with aspheric surfaces and eventually for combined refractive-diffractive lens. It was necessary then to develop a completely new process. The new process was based on the observation that positive photoresist exposes progressively through the thickness of the film on increasing illumination with UV. The authors´ work has been directed at developing an exposure technique which allows a carefully controlled exposure dose at each point in the film. In this way the pattern of light intensities is transformed into vertical relief in the photoresist