Improvement in Transfer Performance for Antireflection Structured Films with Antifouling Properties via Partial-filling Technique

Abstract

Ultraviolet nanoimprint lithography (UV-NIL) is the most effective technique for mass fabrication of antireflection structure (ARS) films. For ARS films applied on touch-panel devices such as mobile phones and tablet computers, however, it is necessary to protect them from fingerprints and dust. Therefore, a UV-curable epoxy resin has been developed with antifouling properties for use with UV-NIL. However, because the developed epoxy resin possesses a high adhesive strength that ultimately reduces the lifetime of nanopatterned molds such as those for ARS, the ARS films herein were fabricated by a partial filling technique. The technique of partial filling uses an incomplete filling ratio of resin, and the work herein specifies the lower and higher filling pressures used for the repetitive transfer test. As a result, up to 200 ARS film imprints were successfully fabricated that exhibited excellent performance using lower pressure filling UV-NIL; while the reflectance obtained was less than 0.5%. In addition, the fabricated ARS films were evaluated for their antifouling properties and their transfer durability performance using the wipe test and the repeated transfer test, respectively.

Fabrication of Moth-eye Antireflective Nanostructures via Oxygen Ion-beam Etching on a UV-curable Polymer

“…One of a most popular methods for moth-eye fabrication is a combination of etching (dry or wet) and nanoimprint lithography (NIL). In the etching process, moth-eye-like structures are formed on a hard material, such as silicon [2], metal [3,4], carbon [7][8][9], or a ceramic [10]. In this process, masking is sometimes used to make regularly arranged patterns.…”

“…For example, Ji et al reported a particle-masking method ('colloidal lithography') that uses a particle monolayer as a mask [11,12]. Processes that do not need masking have also been reported, whereby the moth-eye-like nanostructures are etched on glassy carbon using an oxygen ion beam [7][8][9].…”

Transfer durability of high aspect ratio moth-eye structure on glassy carbon mold using release agent

“…5,6) An anti-reflection structure called a moth-eye structure, simulating the eye of moth, can be created with a single layer and can be effective for a wide range of wavelengths and angles. [7][8][9] The moth-eye structure can be easily fabricated using ultraviolet nanoimprint lithography (UV-NIL), and if a highly durable mold is obtained, the productivity of the anti-reflection structure will be significantly increased. [10][11][12][13] However, the moth-eye structure has a lot of small and sharp needles with a height of several hundred nm to 1 μm and is easily broken during UV-NIL transfer.…”

Evaluation of Scratch Durability of Moth-eye Structures Made of High Hardness Ultraviolet Curable Resin

“…However, this newly developed resin has a strong adhesive force. For this reason, ARS films have been produced by the partial filling method [8][9][10], which involves incompletely filling the resin. In the previous study, the antifouling properties and durability of ARS films produced from high-hardness UV curable resin were evaluated.…”