High-definition LCD panels are starting to be used in automotive instrument panels and center console panels, and displays with optical lenses are coming into use in head-up displays. However, these display panels require excellent visibility both day and night, which calls for the introduction of optical components to the panel surface that have anti-reflection functions over a wide wavelength region and a wide incident angle range. In addition, sensor lenses with excellent environmental resistance are needed to support IoT technology, and there are also demands for components with multiple functions in addition to anti-reflection, such as maintenance of anti-fogging functions.

Moth-eye structures are attracting attention as a new anti-reflection technology that has a low manufacturing cost and realizes optical components with anti-reflection performance over a wide wavelength region and a wide incident angle range not achievable by conventional manufacturing methods. Moth-eye structures have already been practically applied in products such as LCD TVs and single-lens reflex cameras, but further enhancement of anti-reflection characteristics is desired to improve the functionality of optical components.

The researcher, in collaboration with TOA Electric Industrial Co., Ltd., has developed a nanostructure with world top-level low-reflection characteristics and anti-fogging effects that exceed those of moth-eye structures that can achieve low reflectance over a wide incident angle range for a wide range of wavelengths.

The developed technology fabricates anti-reflective nanostructures with functions similar to those of moth-eye structures by injection molding. In addition, a newly developed self-forming column formation technology is used to form column-shaped structures within the nanostructure. This enables world top-level low reflection characteristics over a wide incident angle range. (Reflectance at an incident angle of 60 degrees is reduced to as little as 1/7 compared to a moth-eye film.) Furthermore, it was found that this technology can maintain the super-hydrophilic state of inorganic hydrophilic film for a long time, which was previously a challenge, enabling anti-fogging functions. These characteristics are expected to be applied to large-area curved automotive panels that require high visibility and anti-fogging properties, and contribute to IoT technology through application to ultra-wide-angle lenses with a small radius of curvature and so on.

TOA Electric Industrial Co., Ltd. has received a license for large-area nano concave-convex mold technology from AIST, and has commenced operations of a mass production line for large-area 3D nanostructure molds of up to approximately 50 cm square. It will start sales of large-area nanostructure molds and molded products in the near future.