The moth-eye structure is an anti-reflection structure that is expected to effective over a wide range of wavelengths and angles of incident light. In addition, since the moth-eye structure is a single layer, it can be easily replicated using ultraviolet nanoimprint lithography (UV-NIL). However the moth-eye structure is fragile, because it has a lot of small sharp needles, and it has been reported that the durability decreases as the aspect ratio increases. The moth-eye structure exhibits anti-reflection function even with a low aspect ratio, but in this study, a fragile moth-eye structure with a high aspect ratio was used to facilitate evaluation of the releasability. In this experiment, a glassy carbon mold with high aspect ratio was release treated using a newly developed release agent. Furthermore, using the "partial-filling method" led to a dramatic improvement in the durability when compared to the conventional method using repeated cycles of the UV-NIL machine.

Moth-eye-structure replica mold was fabricated from a glassy carbon master mold by UV-NIL. New UV curable resin with high hardness and antifouling property was used. The motheye-structure was duplicated from the replica mold by use conventional UV curable resin for UV-NIL. Compared with the replica mold by use of a conventional release-agent-free UV curable resin, the moth-eye-structure of new replica mold had superior imprint durability. The reflectance of the imprinted film was below 1% for the 350th imprint. It was that the antifouling property was very important for prolonging life time of replica mold.