Microlenses arrays on large area UV transparent hybrid sol-gel materials for optical tools

Hybrid sol–gel materials are suitable dielectric materials for a range of optical applications, due to the versatility by which their optical and mechanical properties can be adjusted and the easy patterning by various lithographic techniques. We report on the synthesis of engineered epoxy based hybrid organic–inorganic sol–gel materials and on their lithographic processing, specifically applied to the fabrication of microlens arrays. The investigated sol–gel systems exhibit enhanced transparency in the near UV region with respect to most commercial thermoplastic polymers and sol–gel materials, used in embossing and nanoimprinting technology; in addition, they offer a better shape stability and superior mechanical properties, such as higher elastic modulus and hardness, improving the perspectives of the introduction of microstructured and nanostructured surfaces in applications where resistance to environmental mechanical–chemical degradation mechanisms is highly desirable, in particular for outdoor applications.