Some species of the blue Morpho butterfly have a mysterious physical feature of strucural color, because it has both high
reflectivity (>60%) and a single color in too wide angular range (> ± 40° from the normal), which are contradicting with
each other in consideration of the interference phenomena. We have recently proven the principle of the mystery by
extracting the physical essence, and emulating the nano-structures using nano-fabrication techniques. The essence was
special combination of regular and irregular structures at nanometer scale. Such artificial structural color was found to
concern wide applications, because the Morpho-color can produce a single color without pigment in wide angular range
with high reflectivity. Also it makes colors impossible by pigment, and is resistant to fading due to chemical change over
longtime. However, we must overcome several "death valleys" for wide industrial applications. One of the most serious
problems was extremely low throughput in the fabrication process of nano-patterning by the conventional lithography.
This difficulty was solved by use of the nano-imprinting technique. However, from the practical viewpoint, the
enlargement of the mold area for nano-imprinting process was essential. This problem was found to be solved using the
laser fabrication and electroforming processes. Nevertheless, to reproduce the clear blue contrast of the Morpho-color, a
blackening treatment at the film interface was found to be necessary. The blackening processes and conditions by use of
absorbing layers were then estimated and successfully applied to reproduce the clear contrast of the Morpho-blue, which
has been confirmed by the optical measurement of the reflectivity.