Release agent-free low-cost double transfer nanoimprint lithography for moth-eye structure

Glass is one of the essential materials for optical devices due to its transparency. It usually loses about 4% of energy of an incident light at its interface. In order to suppress its reflection, moth-eye structure, which is the nanoscale tapered pillar array, has a remarkable anti-reflection performance. In its fabrication method, nanoimprint lithography has been paid attention due to the availability for large area. However, there are some technological problems such as labor-intensive process and deterioration of the mold's shape happened in surface treatment of release agent to fabricate moth-eye. In order to overcome these problems, we try to use polydimethylsiloxane (PDMS) as the mold due to ease of replication by its low surface energy, and apply to NIL method to fabricate moth-eye structure. As a result, we succeeded to fabricate the moth-eye structure on a glass by this process and raise its transparency from 92% to 96% at visible light range.