MIT Researchers Develop Lightweight, Ultra-Thin Loudspeaker Material
Researchers at MIT have developed a lightweight, paper-thin loudspeaker that can be attached to large surfaces like wallpaper.
Most existing thin-film loudspeakers need to stand up on their own so they can bend and produce sound. "Mounting these loudspeakers onto a surface would impede the vibration and hamper their ability to generate sound," MIT News explains.
With the researchers' new approach, the entire loudspeaker doesn't need to vibrate. Instead, it features "tiny domes on a thin layer of piezoelectric material which each vibrate individually." Space on top and bottom of the domes—"each only a few hair-widths across"—let them vibrate without being damaged.
MIT suggests the tech could be used to cancel out noise in loud places like airplane cockpits, but it could also wind up in theaters and theme park rides, or inside cars, for an immersive entertainment experience. (Work on this project was funded in part by Ford Motor Company.)
"Because it is lightweight and requires such a small amount of power to operate, the device is well-suited for applications on smart devices where battery life is limited," MIT News says.
The loudspeaker is made out of PET. Lasers cut tiny holes into it, and the bottom side is laminated with a layer of piezoelectric material. A vacuum is then applied to the top and a heat source is applied to the bottom.
"Because the PVDF layer is so thin, the pressure difference created by the vacuum and heat source caused it to bulge. The PVDF can’t force its way through the PET layer, so tiny domes protrude in areas where they aren’t blocked by PET." MIT says. "These protrusions self-align with the holes in the PET layer. The researchers then laminate the other side of the PVDF with another PET layer
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