Brighter daylight window design inspired by Morpho butterfly
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A group of Osaka University researchers has developed a novel design for daylight window panes inspired by the structure of the Morpho butterfly wings that shine in a brilliant blue.
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The pane design is expected to help save energy by allowing a room interior to be brightened during the day with natural light alone without turning on artificial illumination.
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“It would never be easy to directly process glass panes according to our design, but you could still allow your room to be brightened up easily, and at low cost, by applying, for example, processed films on your window panes,” said Akira Saito, an associate professor of precision engineering with Osaka University.
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The researchers drew inspiration from the mechanism by which Morpho butterflies develop their wing colors, which some describe as the most beautiful in the world.
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The scientists on the team set their sights on the Morpho butterflies, which live in Latin America, because their wing surfaces have microscopic structures, such as jaggedness and films, that generate beautiful body colors when they reflect light. The hue produced by a similar mechanism is called a “structural color.”
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The back sides of CDs and DVDs appear iridescent, or rainbow-colored, because structural colors are generated by the fine roughness engraved on their surfaces for recording data therein.
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The wings of many Morpho butterfly males, however, do not appear iridescent. Whatever the angle of view, they appear strongly bluish. The researchers therefore thought they could draw on the characteristic feature of the Morpho butterfly wings that allows them not to look rainbow-colored.
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Iridescence, in fact, presents a major challenge. Attempts to process a window pane to allow rays of light to bend or to broaden their reach often end up in the rays assuming colors of the rainbow when they enter the room interior.
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The scientists therefore numerically simulated what would become of the rays of light entering the room after passing through a window pane with microscopic jaggedness of the sort that is found on Morpho butterfly wing surfaces.
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The simulation results showed such a glass pane would allow rays of light to spread more broadly than when a typical window pane is used and the transmitted light would not assume colors of the rainbow.
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